(--)-huperzine a processes and related compositions and methods of treatment

ABSTRACT

The invention provides (1) processes for making substantially-pure (−) huperzine A and substantially-pure (−) huperzine A derivatives; (2) compositions useful in making substantially-pure (−) huperzine A and substantially-pure (−) huperzine A derivatives; and (3) methods of treating or preventing neurological disorders using substantially-pure (−) huperzine A and substantially-pure (−) huperzine A derivatives.

RELATED APPLICATIONS/RESEARCH SUPPORT

This application claims the benefit of priority of U.S. ProvisionalApplication Ser. No. 61/449,198, entitled “Huperzine A”, filed Mar. 4,2011, the entire contents of which are incorporated by reference herein.

BACKGROUND OF THE INVENTION

(−)-Huperzine A (1) is a tricyclic alkaloid produced by the Chinese herbHuperzia serrata. ¹ (−)-Huperzine A (1) is a potent, selective, andreversible inhibitor of acetylcholine esterase (AChE, Ki=23 nM).² Recentstudies have established that this activity may be exploited tocounteract organophosphate chemical warfare agents, such as sarin andVX, by inhibiting their covalent modification of peripheral and cerebralAChE.³ A large body of evidence also suggests that (−)-huperzine A (1)may slow the progression of neurodegenerative diseases, includingAlzheimer's disease.⁴ (−)-Huperzine A (1) is well tolerated in humans,even at doses well above those required clinically.⁵ Consequently,clinical investigation of (−)-huperzine A (1) is a subject of intenseresearch in the pharmaceutical and defense industries.

The primary obstacle to the clinical development of (−)-huperzine A (1)has been one of supply. Extraction from natural sources is low-yielding(average yield=0.011% from the dried herb),^(4a) and overharvesting hascaused a rapid decline in the abundance of Huperziaceae.⁶ Compoundingthese issues, the producing species requires nearly 20 years to reachmaturity.⁶

Total synthesis offers an alternative potential source of huperzine. Anenantioselective synthesis is highly desirable, because (+)-huperzine Ais significantly less potent than the natural (−)-antipode (1).⁷ Thefirst total syntheses of (±)-huperzine A were reported by Kozikowski andXia⁸ and Qian and Ji.⁹ A chiral auxiliary-based route was laterdeveloped by Kozikowski et al.¹⁰ In the interceding years, severalresearch groups have reported modifications to the Kozikowski route,¹¹as well as complete,¹² partial,¹³ and formal¹⁴ routes to huperzine.Nonetheless, Kozikowski's chiral controller-based route,¹⁰ whichproceeds in 16 steps and ca. 2.8% yield, remains the most efficientpublished pathway to synthetic (−)-huperzine A (1).¹⁵

Given the large number of steps and relatively poor stereochemical yieldof known processes for making (−)-huperzine A, and the increasingimportance of (−)-huperzine A as a neuroprotective agent, the needexists for improved methods of making substantially pure (−)-huperzine Ain yields that facilitate scale-up to commercial manufacturing.

SUMMARY OF THE INVENTION

In one embodiment, the invention provides novel processes for makingsubstantially pure (−) huperzine A and substantially pure (−) huperzineA derivatives in relatively large yields through syntheses that employsignificantly fewer steps than known techniques.

In another embodiment, the invention provides novel processes for makingvarious intermediates useful in the manufacture ofpharmaceutically-active ingredients, including substantially pure (−)huperzine A and substantially pure (−) huperzine A derivatives.

In still another embodiment, the invention provides various novelcompositions useful in the manufacture of pharmaceutically-activeingredients, including substantially pure (−) huperzine A andsubstantially pure (−) huperzine A derivatives.

In still another embodiment, the invention provides methods of treatingor preventing a neurological disorder comprising administering eithersubstantially pure (−) huperzine A or a substantially pure (−) huperzineA derivative to a subject who suffers from, or who is at risk ofdeveloping, a neurological disorder.

In still another embodiment, the invention provides a novel process formaking substantially pure (−) huperzine A having the formula:

comprising subjecting an amide of the formula:

to a modified Hoffmann reaction in an aqueous or alcohol solvent(preferably methanol) and in the presence ofbis(trifluoroacetoxyiodo)benzene (PIFA) to form an intermediate,globally deprotecting the intermediate to form (−) huperzine A, andpurifying the (−) huperzine A (e.g. by crystallization and/or flashcolumn chromatography) to yield substantially pure (−) huperzine A.

“Substantially pure (−) huperzine A” as used herein comprises greaterthan about 80% by weight of (−) huperzine A and less than about 20% byweight of (+) huperzine A, more preferably greater than about 90% byweight of (−) huperzine A and less than about 10% by weight of (+)huperzine A, even more preferably greater than about 95% by weight of(−) huperzine A and less than about 5% by weight of (+) huperzine A, andmost preferably greater than about 99% by weight of (−) huperzine A andless than about 1% by weight of (+) huperzine A. A virtually pure (−)huperzine A derivative contains more than 99.5% (−) by weight huperzineA and less than 0.5% by weight (+) huperzine A, more preferably morethan about 99.9% (−) huperzine A and less than about 0.1% (+) huperzineA. A “substantially pure (+) huperzine A derivative” is definedsimilarly with respect to the relative amounts of its (+) and (−)enantiomers.

As used herein, the term (+) huperzine A (or “racemic huperzine A” or“huperzine A racemate”) means a composition comprising about 40-60% of(−) huperzine A and about 40-60% of (+) huperzine A. A racemate of ahuperzine A derivative is defined similarly with respect to the relativeamounts of its (−) and (+) enantiomers.

“Huperzine A derivatives” (e.g. as used in the term “substantially pure(−) huperzine A derivative”) refers to compounds as described in U.S.Pat. No. RE38460, as well as the compounds of formulae (II) and (III)described hereinafter.

In one embodiment, the amide which is subjected to modified Hoffmannreaction as described above is made, preferably one pot, by a processcomprising dehydrating a cyanoalcohol of the formula:

in an organic solvent (preferably toluene), under heated conditions, andin the presence of a Burgess reagent to form a dehydration product, andsubjecting the dehydration product to thermolysis in an alcohol(preferably, aqueous ethanol) and in the presence of a platinum catalystto form the amide. This novel reaction also constitutes an embodiment ofthe invention and can also be done in steps.

In one embodiment, the cyanoalcohol described above is made, preferablyone pot, by subjecting an olefination product which is in substantiallyE isomer form and which has the formula:

to oxidative desilylation (e.g. by reaction with borontrifluoride-acetic acid complex, or a Bronsted acid such as TFA, MSA,FMSA, or tetrafluoroboric acid in an inert solvent, e.g., DCM, orthrough use of Fleming-Tamao oxidation followed by fluoride, hydrogenperoxide and potassium carbonate). In addition to protic acid, removalof the silyl group involves the steps of treatment with fluoride,hydrogen peroxide and potassium carbonate. This novel reaction step alsoconstitutes an embodiment of the invention.

In one embodiment, the olefination product described above is made,preferably one pot, in a process comprising deprotonating an additionalkylation product of the formula:

by reacting the addition alkylation product with lithiumbis(trimethylsilyl) amide (LHMDS) or lithium diisopropyl amide (LDA) andan electrophilic source of cyanide (e.g., para-toluenesulfonyl cyanide,cyanogen bromide, etc.) in an organic solvent (e.g. THF or toluene) toform an α-cyanoketone, subjecting the α-cyanoketone topalladium-catalyzed (e.g., tetrakis(triphenylphosphine)palladium,tris(dibenzylidene acetone) dipalladium, palladiumbis(tri-tert-butylphoshpine) intramolecular enolate heteroarylation inthe presence of a base (most preferably sodium tert-butoxide) and apalladium catalyst to form a cyclized product, and stereoselectivelyolefinating a ketone function of the cyclized product in a Wittigolefination reaction in the presence of a base (e.g. n-butyllithium,sodium bis(trimethylsilyl)amide, lithium bis(trimethylsilyl)amide,potassium bis(trimethylsilyl)amide or lithium diisopropylamide) and inan organic solvent (e.g. THF, diethylether or 1,4-dioxane) to form anolefination product, wherein the stereoselective olefination of thecyclized product kinetically favors formation of the olefination productin E-isomer form. This novel reaction step also constitutes anembodiment of the invention and can also be done in steps.

In one embodiment, the addition alkylation product is made, preferablyone pot, in a process comprising reacting(R)-4-methyl-cyclohex-2-ene-1-one with lithiumdimethylphenylsilylcuprate in a conjugate addition reaction to form anincipient enolate and alkylating the incipient enolate with3-bromo-2-(bromomethyl)-6-methoxypyridine) to form the additionalkylation product. This novel reaction step also constitutes anembodiment of the invention and can also be done in steps.

In still another embodiment, the invention provides a process forcyclizing a β-ketone comprising subjecting an α-cyanoketone topalladium-catalyzed intramolecular enolate heteroarylation, as describedin detail hereinafter.

In still another embodiment, the invention provides a novel process formaking substantially pure (−) huperzine A comprising:

(a) preferably in one pot, reacting (R)-4-methyl-cyclohex-2-ene-1-onewith lithium dimethylphenylsilylcuprate in a conjugate addition reactionto form an incipient enolate and alkylating the incipient enolate with3-bromo-2-(bromomethyl)-6-methoxypyridine) to form an additionalkylation product having the formula:

(b) preferably in one pot, deprotonating the addition alkylation productby reacting the addition alkylation product with lithiumbis(trimethylsilyl) amide (LHMDS) or lithium diisopropyl amide (LDA) inan organic solvent (e.g. THF or toluene) to form an α-cyanoketone,subjecting the α-cyanoketone to palladium-catalyzed intramolecularenolate heteroarylation in the presence of a base (most preferablysodium tert-butoxide) to form a cyclized product, and stereoselectivelyolefinating a ketone function of the cyclized product in a Wittigolefination reaction in the presence of a base (e.g. n-butyllithium,sodium bis(trimethylsilyl)amide, lithium bis(trimethylsilyl)amide,potassium bis(trimethylsilyl)amide or lithium diisopropylamide) and inan organic solvent (e.g. THF, diethylether or 1,4-dioxane) to form anolefination product, wherein the stereoselective olefination of thecyclized product kinetically favors formation of the olefination productin E-isomer form and wherein the olefination product has the formula:

(c) subjecting the olefination product to to oxidative disilylation(e.g. by reaction with boron trifluoride-acetic acid complex, or aBronsted acid such as TFA, MSA, FMSA, or tetrafluoroboric acid in aninert solvent, e.g., DCM, or through use of Fleming-Tamao oxidation) toform a cyanoalcohol having the formula:

(d) preferably in one pot, dehydrating the cyanoalcohol in an organicsolvent (preferably toluene), under heated conditions, and in thepresence of a Burgess reagent to form a dehydration product, andsubjecting the dehydration product to thermolysis in an alcohol(preferably ethanol) and in the presence of a platinum catalyst to formthe amide having the formula:

and(f) subjecting the amide to modified Hoffmann reaction in an aqueous oralcohol solvent (preferably methanol) and in the presence ofbis(trifluoroacetoxyiodo)benzene (PIFA) to form an intermediate,globally deprotecting the intermediate to form (±) huperzine A, andpurifying the (±) huperzine A (e.g. by flash column chromatography) toyield substantially pure (−) huperzine A:

In still another embodiment, the invention provides a compound of theformula (I):

wherein:R₁ is selected from the group consisting of substituted or unsubstitutedC₁-C₆ alkyl and substituted or unsubstituted ether;R₂ and R₅ are independently selected from the group consisting of H,substituted or unsubstituted C₁-C₆ alkyl, and CN, provided that when oneof R₂ or R₅ is CN, the other must be H;X is halogen;R₃ at each occurrence is independently selected from the groupconsisting of H, substituted or unsubstituted C₁-C₆ alkyl, ether, amino,and alkoxy;R₄ is selected from the group consisting of Si(CH₃)₂Ph, substituted orunsubstituted C₁-C₆ alkyl, substituted or unsubstituted C₁-C₆ alkenyl,substituted or unsubstituted aryl, and substituted or unsubstitutedheteroaryl;

A is C, N, or S;

m is 0, 1, or 2;n is 0 or 1;or a pharmaceutically acceptable salt, enantiomer, diastereomer solvateor polymorph thereof.

In still another embodiment, the invention provides a compound of theformula (II):

wherein:R₁ is selected from the group consisting of substituted or unsubstitutedC₁-C₆ alkyl and substituted or unsubstituted ether;R₂ and R₅ are independently selected from the group consisting of H andsubstituted or unsubstituted C₁-C₆ alkyl;R₃ at each occurrence is independently selected from the groupconsisting of H, substituted or unsubstituted C₁-C₆ alkyl, ether, amino,and alkoxy;R₄ is selected from the group consisting of H, OH, and Si(CH₃)₂Ph;R₆ is selected from the group consisting of NH₂, amide, CN, a carboxylicacid derivative (e.g. an ester, a ketone, or a secondary or tertiaryamide), an alcohol, or an aldehyde;R₇ is substituted or unsubstituted C₁-C₆ alkyl, ester, or substituted orunsubstituted aryl;

A is C, N, or S; and

n is 0 or 1;or a pharmaceutically acceptable salt, enantiomer, diastereomer solvateor polymorph thereof.

In one embodiment, compounds of formulae (I) and (II) are used to makepharmacologically active compositions, including substantially pure (−)huperizine A and substantially-pure (−) huperizine A derivatives.

Preferred compounds of the invention include:

Where R¹ and R² are each independently H or a C₁-C₆ alkyl group;

and its primary amine derivatives (where CN is converted to a CH₂NR¹R²group where R¹ and R² are the same as described above);

and its primary amine derivatives (where CN is converted to a CH₂NR¹R²group where R¹ and R² are the same as described above); and

or a pharmaceutically acceptable salt, enantiomer, diastereomer solvateor polymorph thereof.

In still another embodiment, the invention provides a novel process formaking substantially pure (−) huperzine A or a derivative thereof havingthe formula (III):

wherein:R₁ is selected from the group consisting of substituted or unsubstitutedC₁-C₆ alkyl and substituted or unsubstituted ether;R₂ and R₅ are independently selected from the group consisting of H andsubstituted or unsubstituted C₁-C₆ alkyl;R₃ at each occurrence is independently selected from the groupconsisting of H, substituted or unsubstituted C₁-C₆ alkyl, ether, amino,and alkoxy;R₄ is selected from the group consisting of H, OH, and Si(CH₃)₂Ph;R₇ is substituted or unsubstituted C₁-C₆ alkyl, ester, or substituted orunsubstituted aryl;

A is C, N, or S; and

n is 0 or 1;comprising subjecting an amide having the formula (IV):

wherein R₁, R₂, R₃, R₄, R₅, R₇, A, and n are as defined for the compoundof formula (III), to a modified Hoffmann reaction in an aqueous oralcohol solvent (preferably methanol) and in the presence ofbis(trifluoroacetoxyiodo)benzene (PIFA) to form an intermediate,globally deprotecting the intermediate to form (±) huperzine A or a(±)huperzine A derivative, and purifying the (±) huperzine A or(±)huperzine A derivative (e.g. by flash column chromatography) to yieldsubstantially pure (−) huperzine A or a substantially pure (±)huperzineA derivative.

In still another embodiment, the invention provides a process for makingan amide having the formula (IV):

wherein:R₁ is selected from the group consisting of substituted or unsubstitutedC₁-C₆ alkyl and substituted or unsubstituted ether;R₂ and R₅ are independently selected from the group consisting of H andsubstituted or unsubstituted C₁-C₆ alkyl;R₃ at each occurrence is independently selected from the groupconsisting of H, substituted or unsubstituted C₁-C₆ alkyl, ether, amino,and alkoxy;R₄ is selected from the group consisting of H, OH, and Si(CH₃)₂Ph, andH;R₇ is substituted or unsubstituted C₁-C₆ alkyl, ester, or substituted orunsubstituted aryl;

A is C, N, or S; and

n is 0 or 1;comprising dehydrating a cyanoalcohol of the formula (V):

wherein R₁, R₂, R₃, R₅, R₇, A, and n are as defined for the compound offormula (IV), in an organic solvent (preferably toluene), under heatedconditions, and in the presence of a Burgess reagent to form adehydration product, and subjecting the dehydration product tothermolysis in an alcohol (preferably ethanol) and in the presence of aplatinum catalyst to form the amide, wherein the dehydration andthermolysis can be done one-pot or in steps.

In still another embodiment, the invention provides a process for makinga cyanoalcohol of the formula (V):

wherein:R₁ is selected from the group consisting of substituted or unsubstitutedC₁-C₆ alkyl and substituted or unsubstituted ether;R₂ and R₅ are independently selected from the group consisting of H andsubstituted or unsubstituted C₁-C₆ alkyl;R₃ at each occurrence is independently selected from the groupconsisting of H, substituted or unsubstituted C₁-C₆ alkyl, ether, amino,and alkoxy;R₇ is substituted or unsubstituted C₁-C₆ alkyl, ester, or substituted orunsubstituted aryl;

A is C, N, or S; and

n is 0 or 1;comprising subjecting an olefination product which is in substantially Eisomer form and which has the formula (VI):

wherein R₁, R₂, R₃, R₅, R₇, A, and n are as defined in the compound offormula (V), to oxidative disilylation (e.g. by reaction with borontrifluoride-acetic acid complex, or a Bronsted acid such as TFA, MSA,FMSA, or tetrafluoroboric acid in an inert solvent, e.g., DCM, orthrough use of Fleming-Tamao oxidation), wherein the process can be doneone-pot or in steps.

In another embodiment, the invention provides a process for making anolefination product which is in substantially E isomer form and whichhas the formula (VI):

wherein:R₁ is selected from the group consisting of substituted or unsubstitutedC₁-C₆ alkyl and substituted or unsubstituted ether;R₂ and R₅ are independently selected from the group consisting of H andsubstituted or unsubstituted C₁-C₆ alkyl;R₃ at each occurrence is independently selected from the groupconsisting of H, substituted or unsubstituted C₁-C₆ alkyl, ether, amino,and alkoxy;R₇ is substituted or unsubstituted C₁-C₆ alkyl, ester, or substituted orunsubstituted aryl;

A is C, N, or S; and

n is 0 or 1;comprising deprotonating an addition alkylation product having theformula (VII):

wherein R₁, R₂, R₃, R₅, A, and n are as defined in (V), R₄ is selectedfrom the group consisting of Si(CH₃)₂Ph, substituted or unsubstitutedC₁-C₆ alkyl, substituted or unsubstituted C₁-C₆ alkenyl, substituted orunsubstituted aryl, and substituted or unsubstituted heteroaryl, X ishalogen, and m is 0, 1, or 2, by reacting the addition alkylationproduct with lithium bis(trimethylsilyl) amide (LHMDS) or lithiumdiisopropyl amide (LDA) in an organic solvent (e.g. THF or toluene) toform an α-cyanoketone, subjecting the α-cyanoketone topalladium-catalyzed intramolecular enolate heteroarylation in thepresence of a base (most preferably sodium tert-butoxide) to form acyclized product, and stereoselectively olefinating a ketone function ofthe cyclized product in a Wittig olefination reaction in the presence ofa base (e.g. n-butyllithium, sodium bis(trimethylsilyl)amide, lithiumbis(trimethylsilyl)amide, potassium bis(trimethylsilyl)amide or lithiumdiisopropylamide) and in an organic solvent (e.g. THF, diethylether or1,4-dioxane) to form the olefination product, wherein each of theaforementioned reactions can be done one-pot or in steps.

These and other aspects of the invention are described in further detailin the Detailed Description of the Invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 presents a comparison of NMR data of synthetic and natural(−)-huperzine A.

FIG. 2 comprises a catalog of nuclear magnetic resonance and infraredspectra for compositions of the instant invention.

FIG. 3 illustrates that the minor diastereomer of an olefination productmade in accordance with a process of the invention was shown to be ofthe Z-configuration by NOE analysis (500 MHz, CDCl3).

DETAILED DESCRIPTION OF THE INVENTION

The following terms, among others, are used to describe the presentinvention. It is to be understood that a term which is not specificallydefined is to be given a meaning consistent with the use of that termwithin the context of the present invention as understood by those ofordinary skill.

The term “compound”, as used herein, unless otherwise indicated, refersto any specific chemical compound disclosed herein and includestautomers, regioisomers, geometric isomers, and where applicable,optical isomers (e.g. enantiomers), stereoisomers (diastereomers)thereof, as well as pharmaceutically acceptable salts and derivatives(including prodrug forms) thereof. Within its use in context, the termcompound generally refers to a single compound, but also may includeother compounds such as stereoisomers, regioisomers and/or opticalisomers (including racemic mixtures) as well as specific enantiomers orenantiomerically enriched mixtures of disclosed compounds as well asdiastereomers and epimers, where applicable in context. The term alsorefers, in context to prodrug forms of compounds which have beenmodified to facilitate the administration and delivery of compounds to asite of activity.

The term “patient” or “subject” is used throughout the specificationwithin context to describe an animal, generally a mammal and preferablya human, to whom treatment, including prophylactic treatment(prophylaxis), with the compositions according to the present inventionis provided. For treatment of those infections, conditions or diseasestates which are specific for a specific animal such as a human patient,the term patient refers to that specific animal.

The symbol

is used in chemical compounds according to the present invention tosignify that a bond between atoms is a single bond or double bondaccording to the context of the bond's use in the compound, whichdepends on the atoms (and substituents) used in defining the presentcompounds. Thus, where a carbon (or other) atom is used and the contextof the use of the atom calls for a double bond or single bond to linkthat atom with an adjacent atom in order to maintain the appropriatevalence of the atoms used, then that bond is considered a double bond ora single bond.

A “neurological disorder” includes, but is not limited to, anamyloid-related disorder such as Alzheimer's disease and theamyloid-disorders described below, psychiatric disorders such asTourette's syndrome, posttraumatic stress disorder (PTSD), panic andanxiety disorders, obsessive-compulsive disorder, and schizophrenia,developmental disorders such as fragile X syndrome and autism, pain,drug addictions such as alcoholism, neurodegenerative diseases such asParkinson's disease and Huntington's disease, as well as stroke andischemic brain injury, amyotrophic lateral sclerosis, and epilepsy.“Neurological disorder” also includes any disorder, symptom, or effectassociated with or relating to exposure to a neurotoxin, including butnot limited to neurotoxins such as chemical warfare agents.

“Amyloid-related disorders” include diseases associated with theaccumulation of amyloid which can either be restricted to one organ,“localized amyloidosis”, or spread to several organs, “systemicamyloidosis”. Secondary amyloidosis may be associated with chronicinfection (such as tuberculosis) or chronic inflammation (such asrheumatoid arthritis), including a familial form of secondaryamyloidosis which is also seen in Familial Mediterranean Fever (FMF) andanother type of systemic amyloidosis found in long-term hemodialysispatients. Localized forms of amyloidosis include, without limitation,type II diabetes and any related disorders thereof, neurodegenerativediseases such as scrapie, bovine spongiform encephalitis,Creutzfeldt-Jakob disease, Alzheimer's disease, senile systemicamyloidosis (SSA), Cerebral Amyloid Angiopathy, Parkinson's disease, andprion protein related disorders (e.g. prion-related encephalopathies),and rheumatoid arthritis.

The term “effective” is used herein, unless otherwise indicated, todescribe an amount of a compound or composition which, in context, isused to produce or effect an intended result, whether that resultrelates to the inhibition of the effects of a neurological disorder, orto potentiate the effects of a supplementary treatment used in treatinga neurological disorder (e.g. an antipsychotic drug or as otherwisedescribed herein). This term subsumes all other effective amount oreffective concentration terms (including the term “therapeuticallyeffective”) which are otherwise described in the present application.

The terms “treat”, “treating”, and “treatment”, etc., as used herein,refer to any action providing a benefit to a patient at risk for orafflicted by a neurological disorder, including lessening or suppressionof at least one symptom of a neurological disorder, delay in progressionof a neurological disorder or the reduction in likelihood of the onsetof a neurological disorder. Treatment, as used herein, encompasses bothprophylactic and therapeutic treatment.

The term “pharmaceutically acceptable salt” or “salt” is used throughoutthe specification to describe a salt form of one or more of thecompositions herein which are presented to increase the solubility ofthe compound in saline for parenteral delivery or in the gastric juicesof the patient's gastrointestinal tract in order to promote dissolutionand the bioavailability of the compounds. Pharmaceutically acceptablesalts include those derived from pharmaceutically acceptable inorganicor organic bases and acids. Suitable salts include those derived fromalkali metals such as potassium and sodium, alkaline earth metals suchas calcium, magnesium and ammonium salts, among numerous other acidswell known in the pharmaceutical art. Sodium and potassium salts may bepreferred as neutralization salts of carboxylic acids and free acidphosphate containing compositions according to the present invention.The term “salt” shall mean any salt consistent with the use of thecompounds according to the present invention. In the case where thecompounds are used in pharmaceutical indications, the term “salt” shallmean a pharmaceutically acceptable salt, consistent with the use of thecompounds as pharmaceutical agents.

The term “co-administration” shall mean that at least two compounds orcompositions are administered to the patient at the same time, such thateffective amounts or concentrations of each of the two or more compoundsmay be found in the patient at a given point in time. Although compoundsaccording to the present invention may be co-administered to a patientat the same time, the term embraces both administration of two or moreagents at the same time or at different times, including sequentialadministration. Preferably, effective concentrations of allco-administered compounds or compositions are found in the subject at agiven time.

For example, compounds according to the present invention may beadministered with one or more agents that are useful in treating anamyloid-related disorder or a stage of an amyloid-related disorder. Thetype of co-administered agent can vary widely depending on theparticular clinical context. For example, co-administered agents caninclude anti-coagulant or coagulation inhibitory agents, anti-plateletor platelet inhibitory agents, thrombin inhibitors, thrombolytic orfibrinolytic agents, anti-arrhythmic agents, anti-hypertensive agents,calcium channel blockers (L-type and T-type), cardiac glycosides,diuretics, mineralocorticoid receptor antagonists, phosphodiesteraseinhibitors, cholesterol/lipid lowering agents and lipid profiletherapies, anti-diabetic agents, anti-depressants, anti-inflammatoryagents (steroidal and non-steroidal), anti-osteoporosis agents, hormonereplacement therapies, oral contraceptives, anti-obesity agents,anti-anxiety agents, anti-proliferative agents, anti-tumor agents,anti-ulcer and gastroesophageal reflux disease agents, growth hormoneand/or growth hormone secretagogues, thyroid mimetics (including thyroidreceptor antagonist), anti-infective agents, anti-viral agents,anti-bacterial agents, and anti-fungal agents.

More specifically, in the case of Alzheimer's disease, useful additionalagents include but are not limited to cholinesterase inhibitors,antioxidant Ginkobiloba extract, nonsteroidal anti-inflammatory agents,and non-specific NMDA antagonists, such as Ebixa® (Memantine). In thecase of Parkinson's disease, useful additional agents include but arenot limited to carbidopa/levodopa (Sinemet-Bristol Myers Squibb), whichcontrols temor, bradykinesia, balance, and rigidity. Other therapiesinclude dopamine agonists, carbidopa/levodopa therapy, COMT inhibitors,anticholinergics, and MAO inhibitors such as selegiline/deprenyl. In thecase of Type II diabetes, useful additional agents include but are notlimited to biguanides (e.g., metformin), glucosidase inhibitors (e.g.,acarbose), insulins (including insulin secretagogues or insulinsensitizers), meglitinides (e.g., repaglinide), sulfonylureas (e.g.,glimepiride, glyburide and glipizide), biguanide/glyburide combinations(e.g., glucovance), thiozolidinediones (e.g., troglitazone,rosiglitazone and pioglitazone), PPAR-alpha agonists, PPAR-gammaagonists, PPAR alpha/gamma dual agonists, SGLT2 inhibitors, inhibitorsof fatty acid binding protein (aP2), glucagon-like peptide-1 (GLP-1),and dipeptidyl peptidase IV (DP4) inhibitors.

The terms “antagonist” and “inhibitor” are used interchangeably to referto an agent, especially including chemical agents which are specificallydisclosed herein that decreases or suppresses a biological activity,such as to repress an activity of a neurological disorder. “Modulatorsof a neurological disorder” either repress or enhance an activity of aneurological disorder.

The term “acyl” is art-recognized and refers to a group represented bythe general formula hydrocarbylC(O)—, preferably alkylC(O)—.

The term “acylamino” is art-recognized and refers to a moiety having anamino group and an acyl group and may include substitutents on same asotherwise disclosed herein.

The term “aliphatic group” refers to a straight-chain, branched-chain,or cyclic aliphatic hydrocarbon group and includes saturated andunsaturated aliphatic groups, such as an alkyl group, an alkenyl group,and an alkynyl group.

The term “alkenyl”, as used herein, refers to an aliphatic groupcontaining at least one double bond and is intended to include both“unsubstituted alkenyls” and “substituted alkenyls”, the latter of whichrefers to alkenyl moieties having substituents replacing a hydrogen onone or more carbons of the alkenyl group. Such substituents may occur onone or more carbons that are included or not included in one or moredouble bonds. Moreover, such substituents include all those contemplatedfor alkyl groups, as discussed herein, except where stability of themoiety is prohibitive. For example, substitution of alkenyl groups byone or more alkyl, carbocyclyl, aryl, heterocyclyl, or heteroaryl groupsis contemplated.

The terms “alkoxyl” or “alkoxy” as used herein refers to an alkyl group,as defined below, having an oxygen radical attached thereto.Representative alkoxyl groups include methoxy, ethoxy, propyloxy,tert-butoxy and the like.

An “ether” is two hydrocarbons covalently linked by an oxygen.Accordingly, the substituent of an alkyl that renders that alkyl anether is or resembles an alkoxyl, such as can be represented by one of—O-alkyl, —O-alkenyl, —O-alkynyl, —O—(CH₂)_(m)-substituent, where m is 0to 6 and the substituent is an aryl or substituted aryl group, acycloalkyl group, a cycloalkenyl, a heterocycle or a polycycle (two orthree ringed), each of which may be optionally substituted.

The term “alkyl” refers to the radical of saturated aliphatic groups,including straight-chain alkyl groups, branched-chain alkyl groups,cycloalkyl (alicyclic) groups, alkyl-substituted cycloalkyl groups, andcycloalkyl-substituted alkyl groups. In preferred embodiments, astraight chain or branched chain alkyl has 10 or fewer carbon atoms inits backbone (e.g., C₁-C₁₀ for straight chains, C₁-C₁₀ for branchedchains), and more preferably 8 or fewer, and most preferably 6 or fewer.Likewise, preferred cycloalkyls have from 3-10 carbon atoms in theirring structure, and more preferably have 5, 6, 7 or 8 carbons in thering structure.

Moreover, the term “alkyl” (or “lower alkyl”) as used throughout thespecification, examples, and claims is intended to include both“unsubstituted alkyls” and “substituted alkyls”, the latter of whichrefers to alkyl moieties having substituents replacing a hydrogen on oneor more carbons of the hydrocarbon backbone. Such substituents caninclude, for example, a halogen, a hydroxyl, a carbonyl (such as acarboxyl, an alkoxycarbonyl, a formyl, or an acyl), a thiocarbonyl (suchas a thioester, a thioacetate, or a thioformate), an alkoxyl, aphosphoryl, a phosphate, a phosphonate, a phosphinate, an amino, anamido, an amidine, an imine, a cyano, a nitro, an azido, a sulfhydryl,an alkylthio, a sulfate, a sulfonate, a sulfamoyl, a sulfonamido, asulfonyl, a heterocyclyl, an aralkyl, or an aromatic or heteroaromaticmoiety or as otherwise described herein. It will be understood by thoseskilled in the art that the individual substituent chemical moieties canthemselves be substituted. For instance, the substituents of asubstituted alkyl may include substituted and unsubstituted forms ofamino, azido, imino, amido, phosphoryl (including phosphonate andphosphinate), sulfonyl (including sulfate, sulfonamido, sulfamoyl andsulfonate), and silyl groups, as well as ethers, alkylthios, carbonyls(including ketones, aldehydes, carboxylates, and esters), —CF₃, —CN andthe like. Exemplary, non-limiting substituted alkyls are describedherein. Cycloalkyls can be further substituted with alkyls, alkenyls,alkynyls, alkoxys, alkylthios, aminoalkyls, carbonyl-substituted alkyls,—CF₃, —CN, and the like.

Analogous substitutions can be made to alkenyl and alkynyl groups toproduce, for example, without limitation, aminoalkenyls, aminoalkynyls,amidoalkenyls, amidoalkynyls, iminoalkenyls, iminoalkynyls,thioalkenyls, thioalkynyls, carbonyl-substituted alkenyls or alkynyls.

Unless the number of carbons is otherwise specified, “lower alkyl” asused herein means an alkyl group, as defined above, but having from oneto eight carbons, more preferably from one to six carbon atoms in itsbackbone structure. Likewise, “lower alkenyl” and “lower alkynyl” havesimilar chain lengths. Throughout the application, preferred alkylgroups are lower alkyls. In preferred embodiments, a substituentdesignated herein as alkyl is a lower alkyl.

The term “alkynyl”, as used herein, refers to an aliphatic groupcontaining at least one triple bond and is intended to include both“unsubstituted alkynyls” and “substituted alkynyls”, the latter of whichrefers to alkynyl moieties having substituents replacing a hydrogen onone or more carbons of the alkynyl group. Such substituents may occur onone or more carbons that are included or not included in one or moretriple bonds. Moreover, such substituents include all those contemplatedfor alkyl groups, as discussed above, except where stability isprohibitive. For example, substitution of alkynyl groups by one or morealkyl, carbocyclyl, aryl, heterocyclyl, or heteroaryl groups iscontemplated.

The term “alkylthio” refers to an alkyl group, as defined above, havinga sulfur radical attached thereto. In preferred embodiments, the“alkylthio” moiety is represented by one of —S-alkyl, —S-alkenyl,—S-alkynyl, and —S—(CH₂)_(m)—substituent, wherein m is 0 or an integerfrom 1 to 8 and substituent is the same as defined herein and asotherwise below (R₉ and R₁₀ for amine/amino). Representative alkylthiogroups include methylthio, ethylthio, and the like.

The terms “amine” and “amino” are art-recognized and refer to bothunsubstituted and substituted amines, e.g., a moiety that can berepresented, without limitation, by the general formula:

wherein R₉, R₁₀ and R′₁₀ each independently represent a hydrogen, analkyl, an alkenyl, —(CH₂)_(m)—R₈, or R₉ and R₁₀ taken together with theN atom to which they are attached complete a heterocycle having from 4to 8 atoms in the ring structure; R₈ represents an aryl, a cycloalkyl, acycloalkenyl, a heterocycle or a polycycle; and m is zero or an integerin the range of 1 to 8. In preferred embodiments, only one of R₉ or R₁₀can be a carbonyl, e.g., R₉, R₁₀ and the nitrogen together do not forman imide. In certain such embodiments, neither R₉ and R₁₀ is attached toN by a carbonyl, e.g., the amine is not an amide or imide, and the amineis preferably basic, e.g., its conjugate acid has a pK_(a) above 7. Ineven more preferred embodiments, R₉ and R₁₀ (and optionally, R′₁₀) eachindependently represent a hydrogen, an alkyl, an alkenyl, or—(CH₂)_(m)—R₈. Thus, the term “alkylamine” as used herein means an aminegroup, as defined above, having a substituted or unsubstituted alkylattached thereto, i.e., at least one of R₉ and R₁₀ is an alkyl group.Each of the groups which is bonded to the amine group, where applicable,may be optionally substituted.

The term “amido” is art-recognized as an amino-substituted carbonyl andincludes a moiety that can be represented by the general formula:

wherein R₉, R₁₀ are as defined above. Preferred embodiments of the amidewill not include imides that may be unstable.

The term “aralkyl”, as used herein, refers to an alkyl group substitutedwith an aryl group (e.g., an aromatic or heteroaromatic group).

The term “aryl” as used herein includes 5-, 6-, and 7-memberedsingle-ring or aromatic groups containing from zero to four heteroatoms,for example, benzene, pyrrole, furan, thiophene, imidazole, oxazole,thiazole, triazole, pyrazole, pyridine, pyrazine, pyridazine andpyrimidine, and the like. Those aryl groups having heteroatoms in thering structure may also be referred to as “aryl heterocycles”,“heteroaromatics” or “heteroaryl groups”. The aromatic ring can besubstituted at one or more ring positions with such substituents asotherwise described herein, for example, halogen, azide, alkyl, aralkyl,alkenyl, alkynyl, cycloalkyl, polycyclyl, hydroxyl, alkoxyl, amino,nitro, sulfhydryl, imino, amido, phosphate, phosphonate, phosphinate,carbonyl, carboxyl, silyl, ether, alkylthio, sulfonyl, sulfonamido,ketone, aldehyde, ester, heterocyclyl, aromatic or heteroaromaticmoieties, —CF₃, —CN, or the like. The term “aryl” also includespolycyclic ring systems having two or more cyclic rings in which two ormore carbons are common to two adjoining rings (the rings are “fusedrings”) wherein at least one of the rings is aromatic, e.g., the othercyclic rings can be cycloalkyls, cycloalkenyls, cycloalkynyls, arylsand/or heterocyclyls.

The term “carbocycle”, as used herein, refers to an aromatic ornon-aromatic ring in which each atom of the ring is carbon.

The term “carbonyl” is art-recognized and includes such moieties as canbe represented by the general formula:

wherein X is a bond or represents an oxygen or a sulfur, and R₁₁represents, for example without limitation, a hydrogen, an alkyl, analkenyl, —(CH₂)_(m)—R₈ or a pharmaceutically acceptable salt, R′₁₁represents a hydrogen, an alkyl, an alkenyl or —(CH₂)_(m)—R₈, where mand R₈ are as otherwise described herein without limitation. Where X isoxygen and R¹¹ or R′₁₁ is not hydrogen, the formula represents an“ester”. Where X is oxygen, and R₁₁ is as defined above, the moiety isreferred to herein as a carboxyl group, and particularly when R₁₁ ishydrogen, the formula represents a “carboxylic acid”. Where X is oxygen,and R′₁₁ is hydrogen, the formula represents a “formate”. In general,where the oxygen atom of the above formula is replaced by sulfur, theformula represents a “thiocarbonyl” group. Where X is sulfur and R₁₁ orR′₁₁ is not hydrogen, the formula represents a “thioester.” Where X issulfur and R₁₁ is hydrogen, the formula represents a “thiocarboxylicacid.” Where X is sulfur and R′₁₁ is hydrogen, the formula represents a“thioformate.” On the other hand, where X is a bond, and R₁₁ is nothydrogen, the above formula represents a “ketone” group. Where X is abond, and R₁₁ is hydrogen, the above formula represents an “aldehyde”group.

The term “electron withdrawing group” refers to chemical groups whichwithdraw electron density from the atom or group of atoms to whichelectron withdrawing group is attached. The withdrawal of electrondensity includes withdrawal both by inductive and bydelocalization/resonance effects. Examples of electron withdrawinggroups attached to aromatic rings include perhaloalkyl groups, such astrifluoromethyl, halogens, azides, carbonyl containing groups such asacyl groups, cyano groups, and imine containing groups.

The term “ester”, as used herein, refers to a group —C(O)O-substituentwherein the substituent represents, for example, a hydrocarbyl or othersubstitutent as is otherwise described herein.

The terms “halo” and “halogen” as used herein means halogen and includeschloro, fluoro, bromo, and iodo.

The terms “hetaralkyl” and “heteroaralkyl”, as used herein, refers to analkyl group substituted with a hetaryl group.

The terms “heterocycle” or “heterocyclic group” refer to 3- to10-membered ring structures, more preferably 3- to 7-membered rings,whose ring structures include one to four heteroatoms. Heterocycles canalso be polycycles. Heterocyclyl groups include, for example, withoutlimitation, thiophene, thianthrene, furan, pyran, isobenzofuran,chromene, xanthene, phenoxathiin, pyrrole, imidazole, pyrazole,isothiazole, isoxazole, pyridine, pyrazine, pyrimidine, pyridazine,indolizine, isoindole, indole, indazole, purine, quinolizine,isoquinoline, quinoline, phthalazine, naphthyridine, quinoxaline,quinazoline, cinnoline, pteridine, carbazole, carboline, phenanthridine,acridine, pyrimidine, phenanthroline, phenazine, phenarsazine,phenothiazine, furazan, phenoxazine, pyrrolidine, oxolane, thiolane,oxazole, piperidine, piperazine, morpholine, lactones, lactams such asazetidinones and pyrrolidinones, sultams, sultones, and the like. Theheterocyclic ring can be substituted at one or more positions with suchsubstituents as described above without limitation, as for example,halogen, alkyl, aralkyl, alkenyl, alkynyl, cycloalkyl, hydroxyl, amino,nitro, sulfhydryl, imino, amido, phosphate, phosphonate, phosphinate,carbonyl, carboxyl, silyl, ether, alkylthio, sulfonyl, ketone, aldehyde,ester, a heterocyclyl, an aromatic or heteroaromatic moiety, —CF₃, —CN,or the like, and as otherwise described herein.

The terms “heteroaryl” and “hetaryl” include substituted orunsubstituted aromatic single ring structures, preferably 5- to7-membered rings, more preferably 5- to 6-membered rings, whose ringstructures include at least one heteroatom, preferably one to fourheteroatoms, more preferably one or two heteroatoms. The terms“heteroaryl” and “hetaryl” also include up to 20-membered polycyclicring systems having two or more cyclic rings in which two or morecarbons are common to two adjoining rings wherein at least one of therings is heteroaromatic, e.g., the other cyclic rings can becycloalkyls, cycloalkenyls, cycloalkynyls, aryls, heteroaryls, and/orheterocyclyls. Heteroaryl groups include, for example, pyrrole, furan,thiophene, imidazole, oxazole, thiazole, pyrazole, pyridine, pyrazine,pyridazine, and pyrimidine, and the like.

The term “heteroatom” as used herein means an atom of any element otherthan carbon or hydrogen. Preferred heteroatoms are nitrogen, oxygen, andsulfur.

Thus, the terms “heterocyclyl”, “heterocycle”, and “heterocyclic” referto substituted or unsubstituted aromatic or non-aromatic ring structures(which can be cyclic, bicyclic or a fused ring system), preferably 3- to10-membered rings, more preferably 3- to 7-membered rings, whose ringstructures include at least one heteroatom, preferably one to fourheteroatoms, more preferably one or two heteroatoms. The terms“heterocyclyl” and “heterocyclic” also include polycyclic ring systemshaving two or more cyclic rings in which two or more carbons are commonto two adjoining rings wherein at least one of the rings isheterocyclic, e.g., the other cyclic rings can be cycloalkyls,cycloalkenyls, cycloalkynyls, aryls, heteroaryls, and/or heterocyclyls.Heterocyclyl groups include, for example, piperidine, piperazine,pyrrolidine, morpholine, lactones, lactams, and the like.

The term “5- to 20-membered heterocyclic group” or “5- to 14-memberedheterocyclic group” as used throughout the present specification refersto an aromatic or non-aromatic cyclic group having 5 to 20 atoms,preferably 5 to 14 atoms forming the cyclic ring(s) and including atleast one hetero atom such as nitrogen, sulfur or oxygen among the atomsforming the cyclic ring, which is a “5 to 20-membered, preferably 5- to14-membered aromatic heterocyclic group” (also, “heteroaryl” or“heteroaromatic”) in the former case and a “5 to 20-membered”,preferably a “5- to 14-membered non-aromatic heterocyclic group” in thelatter case.

Among the heterocyclic groups which may be mentioned includenitrogen-containing aromatic heterocycles such as pyrrole, pyridine,pyridone, pyridazine, pyrimidine, pyrazine, pyrazole, imidazole,triazole, tetrazole, indole, isoindole, indolizine, purine, indazole,quinoline, isoquinoline, quinolizine, phthalazine, naphthyridine,quinoxaline, quinazoline, cinnoline, pteridine, imidazopyridine,imidazotriazine, pyrazinopyridazine, acridine, phenanthridine,carbazole, carbazoline, perimidine, phenanthroline, phenacene,oxadiazole, benzimidazole, pyrrolopyridine, pyrrolopyrimidine andpyridopyrimidine; sulfur-containing aromatic heterocycles such asthiophene and benzothiophene; oxygen-containing aromatic heterocyclessuch as furan, pyran, cyclopentapyran, benzofuran and isobenzofuran; andaromatic heterocycles comprising 2 or more hetero atoms selected fromamong nitrogen, sulfur and oxygen, such as thiazole, thiadizole,isothiazole, benzoxazole, benzothiazole, benzothiadiazole,phenothiazine, isoxazole, furazan, phenoxazine, pyrazoloxazole,imidazothiazole, thienofuran, furopyrrole, pyridoxazine, furopyridine,furopyrimidine, thienopyrimidine and oxazole.

As examples of the “5- to 14-membered aromatic heterocyclic group” theremay be mentioned preferably, pyridine, triazine, pyridone, pyrimidine,imidazole, indole, quinoline, isoquinoline, quinolizine, phthalazine,naphthyridine, quinazoline, cinnoline, acridine, phenacene, thiophene,benzothiophene, furan, pyran, benzofuran, thiazole, benzthiazole,phenothiazine, pyrrolopyrimidine, furopyridine and thienopyrimidine,more preferably pyridine, thiophene, benzothiophene, thiazole,benzothiazole, quinoline, quinazoline, cinnoline, pyrrolopyrimidine,pyrimidine, furopyridine and thienopyrimidine. The term “heterocyclicgroup” shall generally refer to 3 to 20-membered heterocyclic groups,preferably 3 to 14-membered heterocyclic groups and all subsets ofheterocyclic groups (including non-heteroaromatic or heteroaromatic)subsumed under the definition of heterocyclic group are 3 to 20-memberedheterocyclic groups, preferably 3 to 14-membered heterocyclic groups.

The term “8 to 20-membered heterocyclic group”, or “8 to 14-memberedheterocyclic group” refers to an aromatic or non-aromatic fused bicyclicor tricyclic group having 8 to 20, preferably 8 to 14 atoms forming thecyclic rings (two or three rings) and include at least one hetero atomsuch as nitrogen, sulfur or oxygen among the atoms forming the cyclicrings, which is a “8 to 20-membered”, preferably a “8- to 14-memberedaromatic heterocyclic group” (also, “heteroaryl” or “heteroaromatic”) inthe former case and a “8 to 20-membered”, preferably a “8- to14-membered non-aromatic heterocyclic group” in the latter case. “8 to20-membered heterocyclic groups” and “8 to 14 membered heterocyclicgroups” are represented by fused bicyclic, tricyclic and tetracyclicring structures containing nitrogen atoms such as indole, isoindole,indolizine, purine, indazole, quinoline, isoquinoline, quinolizine,phthalazine, naphthyridine, quinoxaline, quinazoline, cinnoline,pteridine, imidazopyridine, imidazotriazine, pyrazinopyridazine,acridine, phenanthridine, carbazole, carbazoline, perimidine,phenanthroline, phenacene, benzimidazole, pyrrolopyridine,pyrrolopyrimidine and pyridopyrimidine; sulfur-containing aromaticheterocycles such as thiophene and benzothiophene; oxygen-containingaromatic heterocycles such as cyclopentapyran, benzofuran andisobenzofuran; and aromatic heterocycles comprising 2 or more heteroatoms selected from among nitrogen, sulfur and oxygen, such asbenzoxazole, benzothiazole, benzothiadiazole, phenothiazine,benzofurazan, phenoxazine, pyrazoloxazole, imidazothiazole, thienofuran,furopyrrole, pyridoxazine, furopyridine, furopyrimidine andthienopyrimidine, among others.

The term “5- to 14-membered non-aromatic heterocyclic group” as usedthroughout the present specification refers to non-aromatic cyclic grouphaving 5 to 14 atoms forming the cyclic ring and including at least onehetero atom such as nitrogen, sulfur or oxygen among the atoms formingthe cyclic ring. As specific examples there may be mentionednon-aromatic heterocycles such as pyrrolidinyl, pyrrolinyl, piperidinyl,piperazinyl, N-methylpiperazinyl, imidazolinyl, pyrazolidinyl,imidazolidinyl, morpholinyl, tetrahydropyranyl, azetidinyl, oxetanyl,oxathiolanyl, pyridone, 2-pyrrolidone, ethyleneurea, 1,3-dioxolane,1,3-dioxane, 1,4-dioxane, phthalimideandsuccinimide. As examples of the“5- to 14-membered non-aromatic heterocyclic group” there may bementioned preferably, pyrrolidinyl, piperidinyl and morpholinyl, andmore preferably pyrrolidinyl, piperidinyl, morpholinyl and pyrrole.

The term “8- to 14-membered non-aromatic heterocyclic group” as usedthroughout the present specification refers to a non-aromatic fusedcyclic ring system (generally with two or three rings) having 8 to 14atoms forming the cyclic rings (bicyclic or tricyclic) and including atleast one hetero atom such as nitrogen, sulfur or oxygen among the atomsforming the cyclic rings.

The term “5- to 14-membered heterocyclic group” as used throughout thepresent specification refers to an aromatic or non-aromatic cyclic grouphaving 5 to 14 atoms forming the cyclic ring and including at least onehetero atom such as nitrogen, sulfur or oxygen among the atoms formingthe cyclic ring, which is a “5- to 14-membered aromatic heterocyclicgroup” in the former case and a “5- to 14-membered non-aromaticheterocyclic group” in the latter case. Specific examples of the “5- to14-membered heterocyclic group” therefore include specific examples ofthe “5- to 14-membered aromatic heterocyclic group” and specificexamples of the “5- to 14-membered non-aromatic heterocyclic group”.

As the “5- to 14-membered heterocyclic group” there may be mentionedpreferably pyrrolidinyl, piperidinyl, morpholinyl, pyrrole, pyridine,pyridone, pyrimidine, imidazole, indole, quinoline, isoquinoline,quinolizine, phthalazine, naphthyridine, quinazoline, cinnoline,acridine, phenacene, thiophene, benzothiophene, furan, pyran,benzofuran, thiazole, benzothiazole, phenothiazine and carbostyryl, morepreferably pyrrolidinyl, piperidinyl, morpholinyl, pyrrole, pyridine,thiophene, benzothiophene, thiazole, benzothiazole, quinoline,quinazoline, cinnoline and carbostyryl, and even more preferablythiazole, quinoline, quinazoline, cinnoline and carbostyryl, amongothers.

The term “6- to 14-membered aromatic heterocyclic group” as usedthroughout the present specification refers to those substituentsdefined by “5- to 14-membered aromatic heterocyclic group” which have 6to 14 atoms forming the cyclic ring. As specific examples there may bementioned pyridine, pyridone, pyrimidine, indole, quinoline,isoquinoline, quinolizine, phthalazine, naphthyridine, quinazoline,cinnoline, acridine, benzothiophene, benzofuran, thiazole, benzothiazoleand phenothiazine*. “8 to 14-membered aromatic heterocyclic groups”refer to those substituents or radicals having 8 to 14 atoms formingfused two or three cyclic ring systems. Specific examples includeindole, quinoline, isoquinoline, quinolizine, phthalazine,naphthyridine, quinazoline, cinnoline, acridine, benzothiophene,benzofuran, benzothiazole, pyrrolopyrimidine, pyrrolopyrazine,furopyrimidine and phenothiazine, among numerous others.

The term “6- to 14-membered heterocyclic group” as used throughout thepresent specification refers to those substituents defined by “5- to14-membered heterocyclic group” which have 6 to 14 atoms forming thecyclic ring(s). As specific examples there may be mentioned piperidinyl,piperazinyl, N-methylpiperazinyl, morpholinyl, tetrahydropyranyl,1,4-dioxane and phthalimide.

The term “3 to 7-membered heterocyclic group” as used throughout thepresent specification refers to those heterocyclic substituents whichhave 3 to 7 atoms forming the cyclic ring, preferably 5 to 6 atomsforming the cyclic ring.

The term “8 to 14-membered heterocyclic group” as used throughout thepresent specification refers to those substituents defined “8- to14-membered heterocyclic groups which have 8 to 14 atoms forming thefused cyclic ring system.

The term “heterocyclylalkyl”, as used herein, refers to an alkyl groupsubstituted with a heterocycle group.

The term “hydrocarbyl”, as used herein, refers to an optionallysubstituted group that is bonded through a carbon atom and typically hasat least one carbon-hydrogen bond and a primarily carbon backbone, butmay optionally include heteroatoms. Hydrocarbyl groups include, but arenot limited to aryl, heteroaryl, carbocycle, heterocycle, alkyl,alkenyl, alkynyl, and combinations thereof.

The term “lower” when used in conjunction with a chemical moiety, suchas, acyl, acyloxy, alkyl, alkenyl, alkynyl, or alkoxy is meant toinclude groups where there are ten or fewer atoms in the substituent,preferably six or fewer. A “lower alkyl”, for example, refers to analkyl group that contains ten or fewer carbon atoms, preferably six orfewer. In certain embodiments, acyl, acyloxy, alkyl, alkenyl, alkynyl,or alkoxy substituents defined herein are respectively lower acyl, loweracyloxy, lower alkyl, lower alkenyl, lower alkynyl, or lower alkoxy,whether they appear alone or in combination with other substituents,such as in the recitations hydroxyalkyl and aralkyl (in which case, forexample, the atoms within the aryl group are not counted when countingthe carbon atoms in the alkyl substituent).

As used herein, the term “nitro” means —NO₂; the term “halogen”designates —F, —Cl, —Br or —I; the term “sulfhydryl” means —SH; the term“hydroxyl” means —OH; and the term “sulfonyl” means —SO₂—.

The terms “polycyclyl” or “polycyclic group” refer to two or more rings(e.g., cycloalkyls, cycloalkenyls, cycloalkynyls, aryls and/orheterocyclyls) in which two or more atoms are common to two adjoiningrings, e.g., the rings are “fused rings”. Rings that are joined throughnon-adjacent atoms are termed “bridged” rings. Each of the rings of thepolycycle can be substituted with, without limitation, such substituentsas described above, as for example, halogen, alkyl, aralkyl, alkenyl,alkynyl, cycloalkyl, hydroxyl, amino, nitro, sulfhydryl, imino, amido,phosphate, phosphonate, phosphinate, carbonyl, carboxyl, silyl, ether,alkylthio, sulfonyl, ketone, aldehyde, ester, a heterocyclyl, anaromatic or heteroaromatic moiety, —CF3, —CN, or the like.

The phrase “protecting group” as used herein means temporarysubstituents which protect a potentially reactive functional group fromundesired chemical transformations. Examples of such protecting groupsinclude esters of carboxylic acids, silyl ethers of alcohols, andacetals and ketals of aldehydes and ketones, respectively. The field ofprotecting group chemistry has been reviewed (Greene, T. W.; Wuts, P. G.M. Protective Groups in Organic Synthesis, 2^(nd) ed.; Wiley: New York,1991).

The term “substituted” refers to moieties having substituents replacinga hydrogen on one or more carbons of the backbone. It will be understoodthat “substitution” or “substituted with” includes the implicit provisothat such substitution is in accordance with permitted valence of thesubstituted atom and the substituent, and that the substitution resultsin a stable compound, e.g., which does not spontaneously undergotransformation such as by rearrangement, cyclization, elimination, etc.

As used herein, the term “substituted” is contemplated to include allpermissible substituents of organic compounds. In a broad aspect, thepermissible substituents include acyclic and cyclic, branched andunbranched, carbocyclic and heterocyclic, aromatic, non-aromatic andinorganic substituents of organic compounds. The permissiblesubstituents can be one or more and the same or different forappropriate organic compounds. For purposes of this invention, theheteroatoms such as nitrogen may have hydrogen substituents and/or anypermissible substituents of organic compounds described herein whichsatisfy the valences of the heteroatoms. Substituents can include anysubstituents (groups) as otherwise described herein, for example, ahalogen, a hydroxyl, a carbonyl (such as a carboxyl, an alkoxycarbonyl,a formyl, or an acyl), an ether, a thioether, a thiocarbonyl (such as athioester, a thioacetate, or a thioformate), an alkoxyl, a phosphoryl, aphosphate, a phosphonate, a phosphinate, an amino, an amido, an amidine,an imine, a cyano, a nitro, an azido, a sulfhydryl, an alkylthio, asulfate, a sulfonate, a sulfamoyl, a sulfonamido, a sulfonyl, aheterocyclyl, an aralkyl, or an aromatic or heteroaromatic moiety. Itwill be understood by those skilled in the art that the moietiessubstituted on a moiety or chemical group can themselves be substituted.

It will be understood that “substitution” or “substituted with” includesthe implicit proviso that such substitution is in accordance withpermitted valence of the substituted atom and the substituent, and thatthe substitution results in a stable compound, e.g., which does notspontaneously undergo transformation such as by rearrangement,cyclization, elimination, etc. It is acknowledged that the term“unsubstituted” simply refers to a hydrogen substituent or nosubstituent within the context of the use of the term.

Preferred substituents for use in the present invention include, forexample, within context, hydroxyl, carboxyl, cyano (C≡N), nitro (NO₂),halogen (preferably, 1, 2 or 3 halogens, especially on an alkyl,especially a methyl group such as a trifluoromethyl), thiol, alkyl group(preferably, C₁-C₆, more preferably, C₁-C₃), alkoxy group (preferably,C₁-C₆ alkyl or aryl, including phenyl), ether (preferably, C₁-C₆ alkylor aryl), ester (preferably, C₁-C₆ alkyl or aryl) including alkyleneester (such that attachment is on the alkylene group, rather than at theester function which is preferably substituted with a C₁-C₆ alkyl oraryl group), thioether (preferably, C₁-C₆ alkyl or aryl) (preferably,C₁-C₆ alkyl or aryl), thioester (preferably, C₁-C₆ alkyl or aryl),halogen (F, Cl, Br, I), nitro or amine (including a five- orsix-membered cyclic alkylene amine, including a C₁-C₆ alkyl amine orC₁-C₆ dialkyl amine), alkanol (preferably, C₁-C₆ alkyl or aryl), oralkanoic acid (preferably, C₁-C₆ alkyl or aryl). More preferably, theterm “substituted” shall mean within its context of use alkyl, alkoxy,halogen, hydroxyl, carboxylic acid, nitro and amine (including mono- ordi-alkyl substituted amines). Any substitutable position in a compoundaccording to the present invention may be substituted in the presentinvention, but preferably no more than 5, more preferably no more than 3substituents are present on a single ring or ring system. Preferably,the term “unsubstituted” shall mean substituted with one or more Hatoms.

The term “sulfamoyl” is art-recognized and includes a moiety representedby the general formula:

where R₉ and R₁₀ are substituents as described above.

The term “sulfate” is art-recognized and includes a moiety representedby the general formula:

Where R₄₁ is an electron pair, hydrogen, alkyl, cycloalkyl or aryl.

The term “sulfonamido” is art-recognized and includes a moietyrepresented by the general formula:

Where R₉ and R′₁₁ are as described above.

The term “sulfonate” is art-recognized and includes a moiety representedby the general formula:

Where R₄₁ is an electron pair, hydrogen, alkyl, cycloalkyl or aryl.

The term “sulfoxido” or “sulfinyl” is art-recognized and includes amoiety represented by the general formula:

where R₄₄ is is selected from the group consisting of hydrogen, alkyl,alkenyl, alkynyl, cycloalkyl, heterocyclyl, aralkyl or aryl., whichgroups may be optionally substituted.

The term “thioester” is art-recognized and is used to describe a group—C(O)SR⁹ or —SC(O)R⁹ wherein R⁹ represents an optionally substitutedhydrocarbyl group as otherwise described herein.

As used herein, the definition of each expression of alkyl, m, n, etc.when it occurs more than once in any structure, is intended to reflectthe independence of the definition of the same expression in thestructure.

By way of example, certain preferred aromatic and aliphatic rings andtheir derivatives and substituents which may be used as pharmacophoresor substituents in compounds according to the present invention include,but are not limited to, phenyl, benzyl, pyridine, cyclohexadiene,dihydropyridine, tetrahydropyridine, piperidine, pyrazine,tetrahydro-pyrazine, dihydro-pyrazine, piperazine, pyrimidine,dihydro-pyrimidine tetrahydro-pyrimidine, hexahydro-pyrimidine,pyrimidinone, triazine, dihydro-triazine, tetrahydro-triazine,triazinane, tetrazine, dihydro-tetrazine, tetrahydro-tetrazine,tetrazinane, pyrrol, dihydro-pyrrole, pyrrolidine, imidazolidine,dihydro-imidazolidine, imidazole, dihydro-imidazole, azetidine,triazole, dihydro-triazole, triazolidine, tetrazole, dihydro-tetrazole,tetrazolidine, diazepane, tetrahydro-diazepine, dihydro-diazepine,diazepine, oxazole, dihydrooxazole, oxazolidine, isoxazole,dihydroisoxazole, isoxazolidine, thiazole, dihydrothiazole,thiazolidine, isothiazole, dihydroisothiazole, isothiazolidine,oxadiazole, dihydro-oxadiazole, oxadiazolidine, thiadiazole,dihydro-thidiazole, thiadiazolidine, oxazinane, dihydro-oxazinane,dihydro-oxazine, oxazine (including morpholine), thiazinane,dihydro-thiazinane, dihydro-thiazine, thiazine (includingthiomorpholine), thiazine, furan, dihydrofuran, tetrahydrofuran,thiophene, pyridazine-3,6-dione, tetrahydrothiophene, dihydrothiophene,tetrahydrothiophene, dithiolane, dithiole, dithiolone, dioxolane,dioxole, oxathiole, oxathiolane, pyridinone, dioxane, dioxanedione,benzoquinone, dihydro-dioxine, dioxine, pyran, 3,4-dihydro-2H-pyran,pyranone, 2H-pyran-2,3(4H)-dione, oxathiane, dihydro-oxathiine,oxathiine, oxetane, thietane, thiazeto, cyclohexadienone, lactam,lactone, piperazinone, pyrroledione, cyclopentenone, oxazete,oxazinanone, dioxolane, 3,4-dihydro-2H-thiopyran 1,1-dioxide,dioxolanone, oxazolidinone, oxazolone, thiane 1-oxide, thiazinane1-oxide, tetrahydro-thiopyran, thiane 1,1-dioxide, dioxazinane,pyrazolone, 1,3-thiazete, thiazinane 1,1-dioxide,6,7-dihydro-5H-1,4-dioxepine, 1,2-dihydropyridazin-3(4H)-one,pyridine-2,6(1H,3H)-dione, and sugar (glucose, mannose, galactose,fucose, fructose, ribose). Bicyclic and fused rings include, forexample, naphthyl, quinone, quinolinone, dihydroquinoline,tetrahydroquinoline, naphthyridine, quinazoline, dihydroquinazoline,tetrahydroquinazoline, quinoxaline, dihydroquinazoline,tetrahydroquinazoline, pyrazine, quinazoline-2,4(1H,3H)-dione,isoindoline-1,3-dione, octahydro-pyrrolo-pyridine, indoline,isoindoline, hexahydro-indolone, tetrahydropyrrolo oxazolone,hexahydro-2H-pyrrolo[3,4-d]isoxazole, tetrahydro-1,6-naphthyridine,2,3,4,5,6,7-hexahydro-1H-pyrrolo[3,4-c]pyridine, 1H-benzo[d]imidazole,octahydropyrrolo[3,4-c]pyrrole, 3-azabicyclo[3.1.0]hexane,7-azabicyclo[2.2.1]hept-2-ene, diazabicyclo-heptane, benzoxazole,indole, 1,4-diazabicyclo[3.3.1]nonane, azabicyclo-octane,naphthalene-1,4-dione, indene, dihydroindene,2,3,3a,7a-tetrahydro-1H-isoindole, 2,3,3a,4,7,7a-hexahydro-1H-isoindole,1,3-dihydroisobenzofuran, 1-methyl-3a,4,5,6,7,7a-hexahydro-H-indole,3-azabicyclo[4.2.0]octane, 5,6-dihydrobenzo[b]thiophene,5,6-dihydro-4H-thieno[2,3-b]thiopyran, 3,4-dihydropyrazin-2(1H)-one,2H-benzo[b][1,4]thiazine, naphthyridin-4(1H)-one,octahydropyrrolo[1,2-a]pyrazine, imidazo-pyridazine,tetrahydroimidazo-pyridazine, tetrahydropyridazine, thiazinone,5-thia-1-azabicyclo[4.2.0]oct-2-en-8-one,4-thia-1-azabicyclo[3.2.0]heptan-7-one,1,6,7,8-tetrahydroimidazo[4,5-d][1,3]diazepine,8H-thiazolo[4,3-c][1,4]oxazin-4-ium,8H-thiazolo[4,3-c][1,4]thiazin-4-ium, pteridine,thiazolo[3,4-a]pyrazin-4-ium,7-(methylimino)-7H-pyrrolo[1,2-c]thiazol-4-ium, thiazolo-pyrazine,3,7-dioxabicyclo[4.1.0]hept-4-ene,6,7-dihydro-5H-pyrrolo[1,2-a]imidazole,3,3a-dihydrofuro[3,2-b]furan-2(6aH)-one, tetrahydro-3aH-[1,3]dioxolo[4,5-c]pyrrole,7-ethylidene-7H-pyrrolo[1,2-c]thiazol-4-ium,hexahydro-1H-pyrrolo[2,1-c][1,4]oxazine,6,7,8,8a-tetrahydro-1H-pyrrolo[2,1-c][1,4]oxazine,2-azabicyclo[2.2.2]oct-2-ene, 6,6a-dihydrothieno[3,2-b]furan-5(3aH)-one, 4,5-dihydropyridin-3 (2H)-one, 4,7a-dihydro-3aH-[1,3]dioxolo[4,5-c]pyran,6,7-dihydro-1H-furo[3,4-c]pyran-1,3(4H)-dione,3,3a,4,7a-tetrahydro-2H-furo[2,3-b]pyran,2,4a,7,7a-tetrahydro-1H-cyclopenta[c]pyridine,4H-pyrano[3,2-b]pyridine-4,8(5H)-dione,1,2,3,3a,4,7a-hexahydropyrano[4,3-b]pyrrole,2,3,8,8a-tetrahydroindolizin-7(1H)-one,octahydro-1H-pyrido[1,2-a]pyrazin-1-one,2,6,7,8,9,9a-hexahydro-1H-pyrido[1,2-a]pyrazin-1-one,6,7,8,8a-tetrahydropyrrolo[1,2-a]pyrazin-1(2H)-one,hexahydropyrrolo[1,2-a]pyrazin-1(2H)-one, bicyclo[2.2.1]hepta-2,5-diene.

Spiro moieties: 1,5-dioxaspiro[5.5]undecane, 1,4-dioxaspiro[4.5]decane,1,4-diazabicyclo[3.2.1]octane, 5-azaspiro[2.5]octane,5-azaspiro[2.4]heptane, 3,9-diaza-6-azoniaspiro[5.5]undecane,3,4-dihydrospiro[benzo[b][1,4]oxazine-2,1′-cyclohexane],7-oxa-4-azaspiro[2.5]oct-5-ene.

Pharmaceutical compositions comprising combinations of an effectiveamount of at least one STEP-modulating compound according to the presentinvention, and one or more of the compounds otherwise described herein,all in effective amounts, in combination with a pharmaceuticallyeffective amount of a carrier, additive or excipient, represents afurther aspect of the present invention.

The compositions used in methods of treatment of the present invention,and pharmaceutical compositions of the invention, may be formulated in aconventional manner using one or more pharmaceutically acceptablecarriers and may also be administered in controlled-releaseformulations. Pharmaceutically acceptable carriers that may be used inthese pharmaceutical compositions include, but are not limited to, ionexchangers, alumina, aluminum stearate, lecithin, serum proteins, suchas human serum albumin, buffer substances such as phosphates, glycine,sorbic acid, potassium sorbate, partial glyceride mixtures of saturatedvegetable fatty acids, water, salts or electrolytes, such as prolaminesulfate, disodium hydrogen phosphate, potassium hydrogen phosphate,sodium chloride, zinc salts, colloidal silica, magnesium trisilicate,polyvinyl pyrrolidone, cellulose-based substances, polyethylene glycol,sodium carboxymethylcellulose, polyacrylates, waxes,polyethylene-polyoxypropylene-block polymers, polyethylene glycol andwool fat.

The compositions used in methods of treatment of the present invention,and pharmaceutical compositions of the invention, may be administeredorally, parenterally, by inhalation spray, topically, rectally, nasally,buccally, vaginally or via an implanted reservoir. The term “parenteral”as used herein includes subcutaneous, intravenous, intramuscular,intra-articular, intra-synovial, intrasternal, intrathecal,intrahepatic, intralesional and intracranial injection or infusiontechniques. Preferably, the compositions are administered orally,intraperitoneally or intravenously.

Sterile injectable forms of the compositions used in methods oftreatment of the present invention may be aqueous or oleaginoussuspension. These suspensions may be formulated according to techniquesknown in the art using suitable dispersing or wetting agents andsuspending agents. The sterile injectable preparation may also be asterile injectable solution or suspension in a non-toxicparenterally-acceptable diluent or solvent, for example as a solution in1,3-butanediol. Among the acceptable vehicles and solvents that may beemployed are water, Ringer's solution and isotonic sodium chloridesolution. In addition, sterile, fixed oils are conventionally employedas a solvent or suspending medium. For this purpose, any bland fixed oilmay be employed including synthetic mono- or di-glycerides. Fatty acids,such as oleic acid and its glyceride derivatives are useful in thepreparation of injectables, as are natural pharmaceutically-acceptableoils, such as olive oil or castor oil, especially in theirpolyoxyethylated versions. These oil solutions or suspensions may alsocontain a long-chain alcohol diluent or dispersant, such as Ph. Helv orsimilar alcohol.

The pharmaceutical compositions of this invention may be orallyadministered in any orally acceptable dosage form including, but notlimited to, capsules, tablets, aqueous suspensions or solutions. In thecase of tablets for oral use, carriers which are commonly used includelactose and corn starch. Lubricating agents, such as magnesium stearate,are also typically added. For oral administration in a capsule form,useful diluents include lactose and dried corn starch. When aqueoussuspensions are required for oral use, the active ingredient is combinedwith emulsifying and suspending agents. If desired, certain sweetening,flavoring or coloring agents may also be added.

Alternatively, the pharmaceutical compositions of this invention may beadministered in the form of suppositories for rectal administration.These can be prepared by mixing the agent with a suitable non-irritatingexcipient which is solid at room temperature but liquid at rectaltemperature and therefore will melt in the rectum to release the drug.Such materials include cocoa butter, beeswax and polyethylene glycols.

The pharmaceutical compositions of this invention may also beadministered topically, especially to treat skin cancers, psoriasis orother diseases which occur in or on the skin. Suitable topicalformulations are readily prepared for each of these areas or organs.Topical application for the lower intestinal tract can be effected in arectal suppository formulation (see above) or in a suitable enemaformulation. Topically-acceptable transdermal patches may also be used.

For topical applications, the pharmaceutical compositions may beformulated in a suitable ointment containing the active componentsuspended or dissolved in one or more carriers. Carriers for topicaladministration of the compounds of this invention include, but are notlimited to, mineral oil, liquid petrolatum, white petrolatum, propyleneglycol, polyoxyethylene, polyoxypropylene compound, emulsifying wax andwater.

Alternatively, the pharmaceutical compositions can be formulated in asuitable lotion or cream containing the active components suspended ordissolved in one or more pharmaceutically acceptable carriers. Suitablecarriers include, but are not limited to, mineral oil, sorbitanmonostearate, polysorbate 60, cetyl esters wax, cetearyl alcohol,2-octyldodecanol, benzyl alcohol and water.

For ophthalmic use, the pharmaceutical compositions may be formulated asmicronized suspensions in isotonic, pH adjusted sterile saline, or,preferably, as solutions in isotonic, pH adjusted sterile saline, eitherwith our without a preservative such as benzylalkonium chloride.Alternatively, for ophthalmic uses, the pharmaceutical compositions maybe formulated in an ointment such as petrolatum.

The pharmaceutical compositions of this invention may also beadministered by nasal aerosol or inhalation. Such compositions areprepared according to techniques well-known in the art of pharmaceuticalformulation and may be prepared as solutions in saline, employing benzylalcohol or other suitable preservatives, absorption promoters to enhancebioavailability, fluorocarbons, and/or other conventional solubilizingor dispersing agents.

The amount of compound in a pharmaceutical composition of the instantinvention that may be combined with the carrier materials to produce asingle dosage form will vary depending upon the host and diseasetreated, the particular mode of administration. Preferably, thecompositions should be formulated to contain between about 0.05milligram to about 750 milligrams or more, more preferably about 1milligram to about 600 milligrams, and even more preferably about 10milligrams to about 500 milligrams of active ingredient, alone or incombination with at least one additional non-antibody attractingcompound which may be used to treat cancer, prostate cancer ormetastatic prostate cancer or a secondary effect or condition thereof.

It should also be understood that a specific dosage and treatmentregimen for any particular patient will depend upon a variety offactors, including the activity of the specific compound employed, theage, body weight, general health, sex, diet, time of administration,rate of excretion, drug combination, and the judgment of the treatingphysician and the severity of the particular disease or condition beingtreated.

A patient or subject (e.g. a male human) suffering from or at risk ofdeveloping a neurological disorder can be treated by administering tothe patient (subject) an effective amount of (−)-huperzine A and relatedaspects and embodiments according to the present invention includingpharmaceutically acceptable salts, solvates or polymorphs, thereofoptionally in a pharmaceutically acceptable carrier or diluent, eitheralone, or in combination with other known pharmaceutical agents,preferably agents which can assist in treating a neurological disorderor ameliorate the secondary effects and conditions associated with aneurological disorder. This treatment can also be administered inconjunction with other conventional therapies, such as drugs used totreat cognitive and behavioral symptoms of Alzheimer's patients (e.g.Reminyl®, Exelon®, Aricept®, Cognex®, and Namenda®).

These compounds can be administered by any appropriate route, forexample, orally, parenterally, intravenously, intradermally,subcutaneously, or topically, in liquid, cream, gel, or solid form, orby aerosol form.

The active compound is included in the pharmaceutically acceptablecarrier or diluent in an amount sufficient to deliver to a patient atherapeutically effective amount for the desired indication, withoutcausing serious toxic effects in the patient treated. A preferred doseof the active compound for all of the herein-mentioned conditions is inthe range from about 10 ng/kg to 300 mg/kg, preferably 0.1 to 100 mg/kgper day, more generally 0.5 to about 25 mg per kilogram body weight ofthe recipient/patient per day. A typical topical dosage will range from0.01-3% wt/wt in a suitable carrier.

The compound is conveniently administered in any suitable unit dosageform, including but not limited to one containing less than 1 mg, 1 mgto 3000 mg, preferably 5 to 500 mg of active ingredient per unit dosageform. An oral dosage of about 25-250 mg is often convenient.

The active ingredient is preferably administered to achieve peak plasmaconcentrations of the active compound of about 0.00001-30 mM, preferablyabout 0.1-30 μM. This may be achieved, for example, by the intravenousinjection of a solution or formulation of the active ingredient,optionally in saline, or an aqueous medium or administered as a bolus ofthe active ingredient. Oral administration is also appropriate togenerate effective plasma concentrations of active agent, as aretopically administered compositions.

The concentration of active compound in the drug composition will dependon absorption, distribution, inactivation, and excretion rates of thedrug as well as other factors known to those of skill in the art. It isto be noted that dosage values will also vary with the severity of thecondition to be alleviated. It is to be further understood that for anyparticular subject, specific dosage regimens should be adjusted overtime according to the individual need and the professional judgment ofthe person administering or supervising the administration of thecompositions, and that the concentration ranges set forth herein areexemplary only and are not intended to limit the scope or practice ofthe claimed composition. The active ingredient may be administered atonce, or may be divided into a number of smaller doses to beadministered at varying intervals of time.

Oral compositions will generally include an inert diluent or an ediblecarrier. They may be enclosed in gelatin capsules or compressed intotablets. For the purpose of oral therapeutic administration, the activecompound or its prodrug derivative can be incorporated with excipientsand used in the form of tablets, troches, or capsules. Pharmaceuticallycompatible binding agents, and/or adjuvant materials can be included aspart of the composition.

The tablets, pills, capsules, troches and the like can contain any ofthe following ingredients, or compounds of a similar nature: a bindersuch as microcrystalline cellulose, gum tragacanth or gelatin; anexcipient such as starch or lactose, a dispersing agent such as alginicacid, Primogel, or corn starch; a lubricant such as magnesium stearateor Sterotes; a glidant such as colloidal silicon dioxide; a sweeteningagent such as sucrose or saccharin; or a flavoring agent such aspeppermint, methyl salicylate, or orange flavoring. When the dosage unitform is a capsule, it can contain, in addition to material of the abovetype, a liquid carrier such as a fatty oil. In addition, dosage unitforms can contain various other materials which modify the physical formof the dosage unit, for example, coatings of sugar, shellac, or entericagents.

The active compound or pharmaceutically acceptable salt thereof can beadministered as a component of an elixir, suspension, syrup, wafer,chewing gum or the like. A syrup may contain, in addition to the activecompounds, sucrose as a sweetening agent and certain preservatives, dyesand colorings and flavors.

The active compound or pharmaceutically acceptable salts thereof canalso be mixed with other active materials that do not impair the desiredaction, or with materials that supplement the desired action, such asother anticancer agents, antibiotics, antifungals, antiinflammatories,or antiviral compounds.

Solutions or suspensions used for parenteral, intradermal, subcutaneous,or topical application can include the following components: a sterilediluent such as water for injection, saline solution, fixed oils,polyethylene glycols, glycerine, propylene glycol or other syntheticsolvents; antibacterial agents such as benzyl alcohol or methylparabens; antioxidants such as ascorbic acid or sodium bisulfite;chelating agents such as ethylenediaminetetraacetic acid; buffers suchas acetates, citrates or phosphates and agents for the adjustment oftonicity such as sodium chloride or dextrose. The parental preparationcan be enclosed in ampoules, disposable syringes or multiple dose vialsmade of glass or plastic.

If administered intravenously, preferred carriers are physiologicalsaline or phosphate buffered saline (PBS).

In one embodiment, the active compounds are prepared with carriers thatwill protect the compound against rapid elimination from the body, suchas a controlled release formulation, including implants andmicroencapsulated delivery systems. Biodegradable, biocompatiblepolymers can be used, such as ethylene vinyl acetate, polyanhydrides,polyglycolic acid, collagen, polyorthoesters, and polylactic acid.Methods for preparation of such formulations will be apparent to thoseskilled in the art.

Liposomal suspensions may also be pharmaceutically acceptable carriers.These may be prepared according to methods known to those skilled in theart, for example, as described in U.S. Pat. No. 4,522,811 (which isincorporated herein by reference in its entirety). For example, liposomeformulations may be prepared by dissolving appropriate lipid(s) (such asstearoyl phosphatidyl ethanolamine, stearoyl phosphatidyl choline,arachadoyl phosphatidyl choline, and cholesterol) in an inorganicsolvent that is then evaporated, leaving behind a thin film of driedlipid on the surface of the container. An aqueous solution of the activecompound is then introduced into the container. The container is thenswirled by hand to free lipid material from the sides of the containerand to disperse lipid aggregates, thereby forming the liposomalsuspension.

Exemplary Processes and Compounds of the Invention

Scheme 1 below illustrates one preferred synthesis within the scope ofthe instant invention.

The descriptors a, b, c, indicate steps that were performed withintermittent aqueous work-up of products, but without purification ofthe product. Steps 3a and 3d were accomplished by evaporation ofvolatiles, and addition of reagents directly to reaction flask (nointermittent work-up). The route to 5 proceeds in 55% overall yield from1.

The route can begin with the inexpensive, enantiomerically pure reagent(+)-pulegone, which may be transformed to 1 by a four-step procedure,which has been previously published. Lee, H. W.; Ji, S. K.; Lee, I.-Y.C.; Lee, J. H. J. Org. Chem. 1996, 61, 254.

There are many novel features associated with exemplary scheme 1. Forexample, the existing stereochemistry of the starting material can beutilized to control the relative stereochemistry in the product 2.

The conversion of 2 to 3 is not suggested by known techniques. Inparticular, step 2b is the first known example of cyclization of aβ-ketonitrile.

The Wittig reaction (step 2c) is also not suggested by known techniques.Prior workers had obtained mixtures of olefin isomers in the products.We optimized both the substrate and the reaction conditions to obtain adesirable outcome.

The transformation of 4 to 5 is also not suggested by known techniques.Prior workers had relied on a two-step procedure for elimination of thealcohol function (steps 4a). We found that this can be conductedefficiently in one reaction flask using the Burgess reagent.

Step 4b is also not suggested by known techniques. The application ofthe platinum catalyst in the hydration of nitriles to primary amides israre. Additionally, it is known in the literature that such catalystsare generally ineffective for the hydration of tertiary nitriles (suchas that found in 4). Thus, the direct hydration of the nitrile usingthis catalyst constitutes an advance over known synthetic methods.

Intermediates 3, 4, and 5 may potential be used to access other naturalproducts. Compounds such as 5 in particular may be a useful scaffold forsynthesis of other biologically active compounds.

The significant improvement in yield and the notable reduction inprocess steps achieved by the instant invention is illustrated by acomparison with known processes as summarized below.

Summary of Prior Syntheses

PI Stereosel. Steps Overall Yield Kozikowski¹ Racemic 12  6% Qian²Racemic 15 <3.72% (note: yield not reported for the several steps)Kozikowski³ Stereosel 16 2.3% (chiral aux) Mann⁴ Racemic 17  <2% Mann⁴Enantiosel 16 <1.4%  (resolution chiral ester) Fukuyama⁵ Chiral 23 1.8%¹Xia, Y.; Kozikowski, A. P. J. Am. Chem. Soc. 1989, 111, 4116. ²Qian,L.; Ji, R. Tetrahedron Lett. 1989, 30, 2089. ³Yamada, F.; Kozikowski, A.P.; Reddy, E. R.; Pang, Y. P.; Miller, J. H.; McKinney, M. J. Am. Chem.Soc. 1991, 113, 4695. ⁴Lucey, C.; Kelly, S. A.; Mann, J. Org. Biomol.Chem. 2007, 5, 301. ⁵Koshiba, T.; Yokoshima, S.; Fukuyama, T. Org. Lett.2009, 11, 5354.

Further Description of Processes of the Invention

The majority of approaches to huperzine A have relied on introduction ofa four-carbon fragment to a bicyclic structure (retrosynthetic cleavageof bonds a and b in 1, as shown below).

Retrosynthetic Analysis of (−)-Huperzine A (1)

Scheme 2 below provides a further elaboration on the chemical techniquesemployed in the process of Scheme 1 as described above, and indicatesnon-isolated intermediates which are generated in various steps of ourprocesses.

Referring to Schemes 1 and 2, we have developed a novel process in whichdisconnection of two alternative bonds (see 2 in “Retrosyntheticanalysis of (−)-huperzine A (1)” above) forms the ketone andpyridone-based synthons 3 and 4, respectively. The former might beobtained from (R)-4-methyl-cyclohex-2-ene-1-one (5) while3-bromo-2-(bromomethyl)-6-methoxypyridine (6) would serve as afunctional equivalent to 4. The C-4 stereocenter in 5 is used in ourroute to control relative and absolute stereochemistry in the target.Several convenient methods to prepare (R)-4-methylcyclohex-2-ene-1-one(5) have been reported.¹⁶ In preferred embodiments, a straightforwardfour-step sequence starting from (+)-pulegone can be used.^(16a)Dihalopyridines such as 6 have found use in a distinct and significantlymore lengthy route to (−)-huperzine A (1), 14c as well as in thesynthesis of other Lycopodium alkaloids.¹⁷

The successful implementation of this strategy is shown in Scheme 2above. To render the route amenable to large-scale synthesis, weextensively optimized each step, and this allowed many transformationsto be efficiently telescoped (the final synthetic route requires threechromatographic purification steps). Our work commenced with conjugateaddition of lithium dimethylphenylsilylcuprate to(R)-4-methyl-cyclohex-2-ene-1-one (5). Alkylation of the incipientenolate with 3-bromo-2-(bromomethyl)-6-methoxypyridine (6) afforded theaddition-alkylation product 7 as a single detectable diastereomer(1HNMRanalysis), isolated in 84-91% yield after purification (2.0-4.5 gscale).

Kinetically-controlled deprotonation of 7 and trapping of the resultingenolate with para-toluenesulfonyl cyanide,¹⁸ followed by immediate workup of the product mixture, formed the acyanoketone 8 in high purity(est. >95%, ¹H NMR analysis). Rapid isolation of the product wascritical, as the α-cyanoketone 8 underwent disproportionation tostarting material (7) and an α, α-dicyanoketone (not shown) if themixture was allowed to age.

The unpurified α-cyanoketone 8 was then subjected to apalladium-catalyzed intramolecular enolate heteroarylation.¹⁹ Amongseveral catalyst precursors examined, bis(tri-tert-butylphosphine)palladium (0), prepared by the method of Dai and Fu,²⁰ emerged as themost effective. A dramatic dependence on base was observed (Table 1).

TABLE 1 Optimization of the enolate heteroarylation.^(a)

Entry Base mol % Pd Yield 9^(b) Yield 15^(c) Dec._(c) 1 K2CO3 10 <1% 99%— 2 Na2CO3 10 <1% 99% — 3 NaH 10 50% <1% 30% 4 KOt-Bu 10 64% 10% 20% 5NaOt-Bu 5 >99%  <1% <1% ^(a)All reactions were conducted usingPd(Pt-Bu₃)₂ as precatalyst in toluene at 110° C. for 3 h. ^(b)Isolatedyield after purification by flash column chromatography. ^(c)Estimatedby ¹H NMR and LC/MS analysis of the unpurified reaction mixture. Dec. =decomposition.

Thus, in the presence of carbonate bases (entries 1, 2), theprotodebrominated product 15 predominated. Sodium hydride (entry 3)improved conversion to the cyclized product (9), although extensivedecomposition also occurred. Ultimately, we identified sodiumtert-butoxide (entry 5) as optimal, and using this base the product wasobtained in essentially quantitative yield (1H NMR analysis). The nextstep of the sequence called for the stereoselective olefination of theketone function of 9. Treatment of 9 with the lithium ylide derived fromethyltriphenylphosphonium bromide (ether, 24° C.) afforded theolefination product 10 in high yield. A clear trend between E:Zselectivity and concentration was observed (E/Z=1.1, 1.8, 5 at 1.0, 0.1,and 0.01 M, respectively), which is consistent with a salt effect andsuggests the desired E-isomer is the kinetically-favored product.²¹Under optimized conditions, the olefinated product 10 was isolated in71-76% yield from 7 as a 5:1 mixture of E/Z isomers by flash-columnchromatography (4.3-7.4 g scale). By this approach, the entire carbonskeleton of 1 was formed in high overall yield and in four steps on amultigram scale.

Treatment of the olefination product (10) with trifluoromethanesulfonicacid, followed by oxidative desilylation, provided the cyanoalcohol 11in high purity (¹H NMR analysis). The unpurified cyanoalcohol 11 wasefficiently dehydrated by heating with the Burgess reagent (12) intoluene. Thermolysis of the dehydrated product (not shown) in thepresence of the platinum catalyst 13²² in aqueous ethanol afforded theamide 14. Finally, Hofmann rearrangement[bis(trifluoroacetoxy)iodobenzene], global deprotection, andpurification by flash-column chromatography afforded separately(−)-huperzine A (1, 56-70% over four operations) and its olefin isomer(not shown, 11-14%). Synthetic (−)-huperzine A (1) was identical in allrespects (¹H NMR, 13C NMR, IR, three TLC solvent systems, LC/MSretention time, optical rotation) to an authentic sample. Batches of(−)-1 as large as 1.6 g have been prepared.

To date, over 3.5 g of (−)-huperzine A (1) have been prepared by theroute delineated above. Our synthesis proceeds in 35-45% overall yield(16-fold more efficient than any other previously reportedenantioselective route), and requires only three chromatographicpurifications. We envision that this chemistry will provide a reliablesupply of synthetic (−)-huperzine A (1) and will greatly facilitate itsclinical development for neuroprotective and anti-neurodegenerativeapplications.

Those of ordinary skill in the art will appreciate that the variousreactants, reagents, and reactions used in the processes of theinvention may be varied in a number of ways without compromising theefficiency and yield as described herein.

For example, generation of the (−) from huperizine from amide 14 couldbe achieved by a modified Hoffmann reaction usingbis(trifluoroacetoxyiodo)benzene (PIFA) generally in accord with themethods described in Loudon, G. M.; Radhakrishna, A. S.; Almound, M. R.;Blodgett, J. K.; Boutin, R. H. J. Org. Chem., 1984, 49, 4272-4276;Zhang, L.; Kaufmann, G. S.; Pesti, J. A.; Yin, J. J. Org. Chem., 1997,62, 6918-6920; or Schmuck, C.; Geiger, L. Chem. Comm. 2005, 772-774.Ethanol, propanol, or water can be substituted for methanol in theHoffman rearrangement of amide 14.

Dehydration of cyanoalcohol 11 using the Burgess reagent can beaccomplished in a variety of ways, e.g. by using techniques described inK. C. Nicolaou, D. Y.-K. Chen, X. Huang, T. Ling, M. Bella, S. A.Snyder, “Chemistry and Biology of Diazonamide A: First Total Synthesisand Confirmation of the True Structure” J. Am. Chem. Soc. 126,12888-12896 (2004).

Conversion of olefination product 10 to cyanoalcohol 11 as describedherein can be accomplished in a variety of ways. For example,desilylation can be achieved via reaction with boron trifluoride-aceticacid complex, or a Bronsted acid such as TFA, MSA, FMSA, ortetrafluoroboric acid in an inert solvent, e.g., DCM. When a borontrifluoride-acetic acid complex is used, the olefination product 10 canbe oxidized with hydrogen peroxide and KHCO₃. When a Bronsted acid isused, the olefination product 10 may be oxidized with hydrogen peroxide,KHCO₃, and KF. Methods that may be useful for the transformation of thesilyl group to the hydroxy group are also described in Fleming, I.(Chemtracts-Organic Chemistry 1996, 9, 1-64) and Jones, G. R. et al.(Tetrahedron, 1996, 52, 7599-7662).

The Wittig olefination reaction used to convert cyclized product 9 toolefination product 10 could be modified in a variety of ways, e.g.through use of bases such as n-butyllithium, sodiumbis(trimethylsilyl)amide, lithium bis(trimethylsilyl)amide, potassiumbis(trimethylsilyl)amide or lithium diisopropylamide in solvents such asTHF, diethylether or 1,4-dioxane. See Chem. Rev. 1989, 89, 863; ModernCarbonyl Olefination 2004, 1-17; Liebigs Ann. Chem. 1997, 1283.

In the cyanation of the enolate generated by deprotonation ofaddition-alkylation product 7, THF can be substituted for toluene in thecyanation reaction. See D. Kahne and D. B. Collum, Tetrahedron Lett.,5011 (1981), and lithium bis(trimethylsilyl) amide (LHMDS) can besubstituted for lithium diisopropyl amide (LDA).

Any of the methods described in the references of note 16 can be used toprepare the starting material (R)-4-methyl-cyclohex-2-ene-1-one 1.

Further details regarding the above-described processes are presentedbelow in the illustrative experimental section.

Experimental Section General Experimental Procedures

All reactions were performed in single-neck, flame-dried, round-bottomedflasks fitted with rubber septa under a positive pressure of argon,unless otherwise noted. Air and moisture-sensitive liquids weretransferred via syringe or stainless steel cannula, or were handled in anitrogen-filled drybox (working oxygen level <1 ppm). Organic solutionswere concentrated by rotary evaporation at 30-33° C. Flash-columnchromatography was performed as described by Still et al,¹ employingsilica gel (60 Å, 40-63 μm particle size) purchased from SorbentTechnologies (Atlanta, Ga.). Analytical thin-layered chromatography(TLC) was performed using glass-plates pre-coated with silica gel (1.0mm, 60 Å pore size) impregnated with a fluorescent indicator (254 nm).TLC plates were visualized by exposure to ultraviolet light (UV) or/andsubmersion in aqueous potassium permagnate solution (KMnO₄), followed bybrief heating on a hot plate (120° C., 10-15 s).

Materials.

Commercial solvents and reagents were used as received with thefollowing exceptions. Benzene, dichloromethane, ether, and toluene werepurified according to the method of Pangborn et al.² Tetrahydrofuran wasdistilled from sodium/benzophenone under an atmosphere of nitrogenimmediately before use. Methanol was distilled from magnesium methoxideunder an atmosphere of nitrogen immediately before use.Hexamethylphosphoramide was distilled from calcium hydride and storedunder nitrogen. 4-Å Molecular sieves were activated by heating overnightin vacuo (200° C., 200 mTorr), stored in a gravity oven (120° C.), andwere flame-dried in vacuo (100 mTorr) immediately before use. Solutionsof phenyldimethylsilyllithium in tetrahydrofuran were prepared accordingto the procedure of Fleming and co-workers.³(R)-4-Methyl-cyclohexe-2-ene-1-one (5) was prepared from (+)-pulegoneaccording to the procedure of Lee and co-workers.⁴3-Bromo-2-(bromomethyl)-6-methoxypyridine (6) was prepared according tothe procedure of Kelly and co-workers.⁵Bis(tri-tert-butylphosphine)palladium (0) was prepared according to theprocedure of Dai and Fu.⁶ Methyl N-(triethylammoniumsulfonyl)carbamate(Burgess reagent, 12) was prepared according to the procedure of Burgessand co-workers.⁷ Hydrido(hydroxydimethylphosphino) [hydrogenbis(hydroxydimethylphosphino)]platinum (II) (13) was prepared accordingto the procedure of Ghaffar and Parkins.⁸ Ethyltriphenylphosphoniumbromide was recrystallized from water, and the resulting crystals weredried for 24 h at 50° C. in vacuo.

Instrumentation.

Proton nuclear magnetic resonance spectra (¹H NMR) were recorded at 400or 500 MHz at 24° C., unless otherwise noted. Chemical shifts areexpressed in parts per million (ppm, δ scale) downfield fromtetramethylsilane and are referenced to residual protium in the NMRsolvent (CHCl₃, δ 7.26). Data are represented as follows: chemicalshift, multiplicity (s=singlet, d=doublet, t=triplet, q=quartet,m=multiplet and/or multiple resonances, br=broad, app=apparent),integration, coupling constant in Hertz, and assignment.Proton-decoupled carbon nuclear magnetic resonance spectra (¹³C NMR)were recorded at 100 or 125 MHz at 24° C., unless otherwise noted.Chemical shifts are expressed in parts per million (ppm, δ scale)downfield from tetramethylsilane and are referenced to the carbonresonances of the solvent (CDCl₃, δ 77.0). Distortionless enhancement bypolarization transfer spectra [DEPT (135)] were recorded at 100 or 125MHz at 24° C., unless otherwise noted. ¹³C NMR and DEPT (135) data arecombined and represented as follows: chemical shift, carbon type[obtained from DEPT (135) experiments]. Attenuated total reflectanceFourier transform infrared spectra (ATR-FTIR) were obtained using aThermo Electron Corporation Nicolet 6700 FTIR spectrometer referenced toa polystyrene standard. Data are represented as follows: frequency ofabsorption (cm⁻¹), intensity of absorption (s=strong, m=medium, w=weak,br=broad). High-resolution mass spectrometry (HRMS) data were obtainedusing a Waters UPLC/HRMS instrument equipped with a dual API/ESIhigh-resolution mass spectrometry detector and photodiode arraydetector. Unless otherwise noted, samples were eluted over areverse-phase C₁₈ column (1.7 m particle size, 2.1×50 mm) with a lineargradient of 5% acetonitrile-water containing 0.1% formic acid→95%acetonitrile-water containing 0.1% formic acid over 4 min, followed by100% acetonitrile containing 0.1% formic acid for 1 min, at a flow rateof 600 μL/min. Optical rotations were measured on a Perkin Elmerpolarimeter equipped with a sodium (589 nm, D) lamp. Optical rotationdata are represented as follows: specific rotation ([α]²⁰ _(n)),concentration (g/mL), and solvent.

Synthetic Procedures.⁹

Step 1: Addition-Alkylation of (R)-4-Methyl-cyclohexe-2-ene-1-one (5)(Addition-Alkylation Product 7)

Hexamethylphosphoramide (11.4 mL, 65.4 mmol, 3.60 equiv) was addeddropwise via syringe to a stirred suspension of cuprous iodide (3.46 g,18.2 mmol, 1.00 equiv) in tetrahydrofuran (36 mL) at 24° C. Theresulting mixture was cooled to −78° C. A solution ofdimethylphenylsilyllithium in tetrahydrofuran (0.46 M, 79.0 mL, 36.3mmol, 2.00 equiv) was added dropwise via syringe pump over 30 min to thecold brown suspension. Upon completion of the addition, the mixture waswarmed to 0° C. The resulting solution was stirred for 1 h at 0° C. Themixture was then cooled to −78° C. (R)-4-Methyl-cyclohexe-2-ene-1-one(5, 2.00 g, 18.2 mmol, 1.00 equiv) was added dropwise via syringe over 5min. Upon completion of the addition, the reaction mixture was warmed to−23° C. The warmed solution was stirred for 3 h at −23° C. The reactionmixture was then cooled to −78° C. A solution of3-bromo-2-(bromomethyl)-6-methoxypyridine (6) in tetrahydrofuran (0.50M, 40.0 mL, 20.0 mmol, 1.10 equiv) was added dropwise via cannula over30 min to the cold reaction mixture. Upon completion of the addition,the reaction mixture was warmed to −23° C. The warmed solution wasstirred for 1 h at −23° C. The product mixture was then warmed over 30min to 24° C. The warmed product mixture was eluted through a pad ofcelite (length/diameter=3/9 cm). The celite pad was washed sequentiallywith saturated aqueous sodium bicarbonate solution (100 mL), ethylacetate (250 mL), saturated aqueous sodium bicarbonate solution (100mL), and ethyl acetate (250 mL). The biphasic filtrate was collected andtransferred to a separatory funnel. The layers that formed wereseparated. The organic layer was washed sequentially with saturatedaqueous sodium bicarbonate solution (2×200 mL), distilled water (200mL), and saturated aqueous sodium chloride solution (200 mL). The washedorganic layer was dried over sodium sulfate. The dried solution wasfiltered and the filtrate was concentrated. The residue obtained waspurified by flash-column chromatography (eluting with 5% ethylacetate-hexanes) to afford the addition-alkylation product 7 as apale-yellow, viscous oil (7.37 g, 91%).

R_(f)=0.27 (5% ethyl acetate-hexanes, KMnO₄). [α]²⁰ _(n)=−40.8 (c 0.10,CHCl₃). ¹H NMR (500 MHz, CDCl₃), δ 7.55 (d, 1H, J=8.5 Hz, H₁), 7.45 (dd,2H, J=8.0, 2.0 Hz, H₁₂), 7.33-7.29 (m, 3H, H₁₂), 6.42 (d, 1H, J=8.5 Hz,H₂), 3.79 (s; 3H, H₃), 3.22-3.12 (m, 2H, H₄/H₅), 2.84 (dd, 1H, J=14.5,4.5 Hz, H₄), 2.58-2.52 (m, 1H, H₉), 2.23-2.17 (m, 1H, H₉), 2.05-1.94 (m,2H, H₇/H₈), 1.82-1.75 (m, 1H, H₈), 1.15 (t, 1H, J=6.5 Hz, H₆), 1.00 (d,3H, 6.5 Hz, H₁₀), 0.32 (app s, 6H, H₁₁). ¹³C NMR (125 MHz, CDCl₃), δ214.8 (C), 162.2 (C), 154.7 (C), 142.4 (CH), 138.1 (C), 134.0 (CH),129.3 (CH), 128.0 (CH), 112.2 (C), 110.1 (CH), 53.6 (CH₃), 47.1 (CH),40.3 (CH₂), 37.3 (CH₂), 34.3 (CH), 31.1 (CH₂), 29.3 (CH), 23.9 (CH₃),−3.0 (CH₃), −3.6 (CH₃). IR (ATR-FTIR), cm⁻¹: 2951 (br), 1709 (s), 1575(s), 1459 (s), 1417 (s), 1295 (m), 1250 (m), 1111 (m), 1037 (m), 1014(m), 820 (s), 734 (m), 701 (m). HRMS-CI(m/z): [M+H]⁺ calcd forC₂₂H₂₉BrNO₂Si, 446.1146/448.1125; found, 446.1147/448.1124.

Steps 2a-c: Synthesis of the Olefination Product 10

Step 2a: Cyanation of the Addition-Alkylation Product 7 (a-Cyanoketone8)

A solution of lithium hexamethyldisilazide in toluene (1.00 M, 49.7 mL,49.7 mmol, 3.00 equiv) was added dropwise over 15 min via syringe pumpto a stirred solution of the addition-alkylation product 7 (7.37 g, 16.6mmol, 1.00 equiv) in toluene (170 mL) at −78° C. Upon completion of theaddition, the reaction mixture was warmed to 0° C. The warmed solutionwas stirred for 15 min at 0° C. The mixture was then cooled to −78° C. Asolution of p-toluenesulfonyl cyanide in toluene (1.00 M, 18.2 mL, 18.2mmol, 1.10 equiv) was added quickly (<1 min) via syringe to the coldreaction mixture. The reaction mixture was stirred for 1 min at −78° C.The cold product mixture was rapidly diluted with 100 mM aqueous sodiumphosphate buffer solution (pH 7, 30 mL). The product mixture was allowedto warm over 30 min to 24° C., with stirring. The warmed product mixturewas diluted with ethyl acetate (200 mL). The diluted product mixture wastransferred to a separatory funnel that had been charged with 100 mMaqueous sodium phosphate buffer solution (pH 7, 150 mL). The layers thatformed were separated. The aqueous layer was extracted with ethylacetate (3×150 mL). The organic layers were combined, and the combinedorganic layers were dried over sodium sulfate. The dried solution wasfiltered and the filtrate was concentrated to afford the unpurifiedα-cyanoketone 8 as a pale-yellow, viscous oil. ¹H NMR analysis (400 MHz,CDCl₃) indicated >95% conversion to the cyanoketone 8 (mixture of(R)-α-cyanoketone, (S)-a-cyanoketone, and β-hydroxy-a,3-unsaturatednitrile isomers). The product so obtained was used directly in thefollowing step.

The α-cyanoketone 8 was found to be unstable towards purification byflash-column chromatography. Therefore, further characterization was notattempted.

Step 2b: Cyclization of the α-Cyanoketone 8 (Tricycle 9)

A 500-mL round-bottomed flask fused to a Teflon-coated valve was chargedwith the unpurified α-cyanoketone 8 (16.6 mmol, 1.00 equiv, assumingquantitative yield in the preceding step). The residue was dried byazeotropic distillation with benzene (5.0 mL). The vessel was sealed andthe sealed vessel was transferred to a nitrogen-filled drybox. Sodiumtert-butoxide (1.75 g, 18.2 mmol, 1.10 equiv),bis(tri-tert-butylphosphine)palladium (0) (423 mg, 828 μmol, 0.05 equiv)and toluene (170 mL) were added sequentially to the flask. The vesselwas sealed, and the sealed vessel was removed from the drybox. Thereaction vessel was placed in an oil bath that had been preheated to110° C. The reaction mixture was stirred and heated for 12 h at 110° C.The reaction vessel was removed from the oil bath and the productmixture was allowed to cool over 30 min to 24° C. The cooled productmixture was diluted with dichloromethane (300 mL). The diluted mixturewas transferred to a separatory funnel that had been charged withsaturated aqueous sodium bicarbonate solution (400 mL). The layers thatformed were separated. The aqueous layer was extracted withdichloromethane (3×500 mL). The organic layers were combined, and thecombined organic layers were dried over sodium sulfate. The driedsolution was filtered and the filtrate was concentrated to afford theunpurified cyclized product 9 as a pale-yellow, viscous oil. ¹H NMRanalysis (400 MHz, CDCl₃) indicated >95% conversion to the cyclizedproduct 9. The product so obtained was used directly in the followingstep. An analytically pure sample of the cyclized product 9 was obtainedby flash-column chromatography (eluting with 5% ethyl acetate-hexanes):

R_(f)=0.23 (5% ethyl acetate-hexanes, KMnO₄). ¹H NMR (500 MHz, CDCl₃), δ7.64 (d, 1H, J=9.0 Hz, H₁), 7.51 (dd, 2H, J=7.0, 1.5 Hz, H₁₁), 7.39-7.29(m, 3H, H₁₁), 6.74 (d, 1H, J=8.5 Hz, H₂), 3.91 (s, 3H, H₃), 3.14 (dd,1H, J=18.0, 4.5 Hz, H₄), 2.95-2.92 (m, 1H, H₅), 2.82-2.77 (m, 2H,H₄/H₈), 2.15 (dd, 1H, J=13.5, 10.0 Hz, H₈), 1.85-1.78 (m, 1H, H₇), 1.32(dd, 1H, J=10.0, 6.5 Hz, H₆), 0.75 (d, 3H, J=6.5 Hz, H₉), 0.40 (s, 3H,H₁₀), 0.37 (s, 3H, H₁₀). 13C NMR (125 MHz, CDCl₃), δ 206.0 (C), 164.1(C), 149.5 (C), 138.5 (CH), 136.9 (C), 134.1 (CH), 129.8 (CH), 128.3(CH), 125.1 (C), 119.2 (C), 111.0 (CH), 53.9 (CH₃), 52.4 (CH₂), 49.9(C), 44.9 (CH), 42.4 (CH₂), 38.1 (CH), 28.2 (CH), 21.8 (CH₃), −3.4(CH₃), −3.8 (CH₃). IR (ATR-FTIR), cm⁻¹: 2955 (br), 2268 (w), 1736 (s),1713 (w), 1599 (m), 1576 (w), 1476 (s), 1424 (m), 1321 (m), 1264 (m),1130 (m), 1112 (m), 1028 (m), 824 (s), 737 (w), 704 (m). HRMS-CI(m/z):[M+H]⁺ calcd for C₂₃H₂₇N₂O₂Si, 391.1837; found, 391.1839.

Step 2c: Olefination of the Cyclized Product 9 (Alkene 10)

In a nitrogen-filled drybox, a 500-mL round-bottomed flask was chargedsequentially with ethyltriphenylphosphonium bromide (7.38 g, 19.9 mmol,1.20 equiv) and lithium hexamethyldisilazide (3.33 g, 19.9 mmol, 1.20equiv). The flask was sealed with a rubber septum, and the sealed flaskwas removed from the drybox. Ether (200 mL) was added to the flask viasyringe. The resulting orange suspension was stirred for 1 h at 24° C.During this time, the solids dissolved to form a clear orange solution.In a separate flask, a solution of the unpurified cyclized product 9(16.6 mmol, 1.00 equiv, assuming quantitative yield in the preceedingstep) in ether (1.5 L) was prepared. The orange ylide solution wastransferred via cannula over 10 min to the flask containing the cyclizedproduct 9 at 24° C. The reaction mixture was stirred for 12 h at 24° C.The product mixture was poured into a separatory funnel that had beencharged with distilled water (500 mL) and ethyl acetate (500 mL). Thelayers that formed were separated. The aqueous layer was extracted withethyl acetate (2×500 mL). The organic layers were combined and thecombined organic layers were dried over sodium sulfate. The driedsolution was filtered and the filtrate was concentrated. The residueobtained was purified by flash-column chromatography (eluting with 5%ethyl acetate-hexanes) to yield the olefination product 10 as apale-yellow, viscous oil (4.74 g, 71% from 7, 5:1 mixture of E:Zdiastereomers).

R_(f)=0.20 (5% ethyl acetate-hexanes, KMnO₄). ¹H NMR (400 MHz, CDCl₃,5:1 mixture of diastereomers): E-olefin (major diastereomer), δ 7.69 (d,1H, J=8.4 Hz, Hi), 7.54-7.48 (m, 2H, H₁₁), 7.39-7.34 (m, 3H, H₁₁), 6.64(d, 1H, J=8.8 Hz, H₂), 5.95 (q, 1H, J=6.8 Hz, H₁₂), 3.90 (s, 3H, H₃),3.37-3.34 (m, 1H, H₅), 2.86 (dd, 1H, J=17.6, 4.8 Hz, H₄), 2.60-2.55 (m,1H, H₄), 2.50 (dd, 1H, J=12.4, 6.0 Hz, H₈), 1.79-1.68 (m, 2H, H₇/H₈),1.72 (d, 3H, J=6.8 Hz, H₁₃), 0.77 (dd, 1H, J=8.8, 5.6 Hz, H₆), 0.63 (d,3H, J=6.8 Hz, H₉), 0.37 (s, 3H, H₁₀), 0.36 (s, 3H, H₁₀); Z-olefin (minordiastereomer), δ 7.78 (d, 1H, J=8.8 Hz, H₁), 7.54-7.48 (m, 2H, H₁₁),7.39-7.34 (m, 3H, H₁₁), 6.67 (d, 1H, J=8.8 Hz, H₂), 5.60 (q, 1H, J=7.6Hz, H₁₂), 3.91 (s, 3H, H₃), 2.94 (dd, 1H, J=17.6, 4.8 Hz, H₄), 2.75-2.70(m, 1H, H₅), 2.62-2.46 (m, 2H, H₄/H₈), 2.02 (d, 3H, J=8 Hz, H₁₃),1.79-1.68 (m, 2H, H₇/H₈), 0.67-0.60 (m, 1H, H₆), 0.62 (d, 3H, J=6 Hz,H₉), 0.36 (s, 3H, H₁₀), 0.33 (s, 3H, H₁₀). ¹³C NMR (100 MHz, CDCl₃, 5:1mixture of diastereomers): E-olefin (major diastereomer), δ 163.3 (C),151.9 (C), 138.3 (C), 137.9 (CH), 134.2 (C), 134.0 (CH), 129.4 (CH),128.1 (CH), 127.4 (C), 122.7 (C), 118.2 (CH), 109.5 (CH), 53.7 (CH₃),50.4 (CH₂), 44.4 (C), 42.2 (CH₂), 34.7 (CH), 30.7 (C), 27.7 (CH), 22.3(CH₃), 12.7 (CH₃), −2.9 (CH₃), −3.3 (CH₃); Z-olefin (minordiastereomer), δ 163.3 (C), 152.3 (C), 138.4 (C), 138.0 (CH), 134.0(CH), 132.7 (C), 129.3 (CH), 128.0 (CH), 127.2 (C), 124.6 (C), 120.6(CH), 109.6 (CH), 53.8 (CH₃), 51.1 (CH₂), 43.3 (CH₂), 41.9 (CH), 39.7(C), 34.7 (CH), 27.9 (CH), 22.0 (CH₃), 12.8 (CH₃), −3.0 (CH₃), −3.5(CH₃). IR (ATR-FTIR), cm⁻¹: 2952 (br), 1598 (m), 1578 (w), 1476 (s),1426 (m), 1320 (m), 1264 (m), 1112 (w), 1031 (w), 824 (m), 733 (w), 702(w). HRMS-CI(m/z): [M+H]⁺ calcd for C₂₅H₃₁N₂OSi, 403.2201; found,403.2198.

The minor diastereomer was shown to be of the Z-configuration by NOEanalysis (500 MHz, CDCl₃). See FIG. 3.

Steps 3a-d: Conversion of the Olefination Product 10 to (−)-Huperzine A(1)

Step 3a: Tamao-Fleming Oxidation of the Olefination Product 10 (Alcohol11)

Trifluoromethanesulfonic acid (2.29 mL, 26.0 mmol, 2.20 equiv) was addeddropwise via syringe over 5 min to a stirred solution of the olefinationproduct 10 (4.74 g, 11.8 mmol, 1.00 equiv) in dichloromethane (59 mL) at0° C. The reaction mixture was allowed to warm over 10 min to 24° C. Thereaction mixture was stirred for 1 h at 24° C. The solvent wasevaporated under reduced pressure. The residue obtained was dissolved inN,N-dimethylformamide (94 mL). Potassium carbonate (4.89 g, 35.4 mmol,3.00 equiv) and distilled water (47 mL) were then added in sequence. Theresulting milky solution was stirred for 15 min at 24° C. A solution oftetrabutylammonium fluoride in tetrahydrofuran (1.0 M, 177 mL, 177 mmol,15.0 equiv) was added, and the resulting mixture was stirred for 1 h at24° C. A solution of hydrogen peroxide in water (35%, 30.4 mL, 354 mmol,30.0 equiv) was then added rapidly and the resulting mixture was warmedto 40° C. The reaction mixture was stirred and heated for 12 h at 40° C.The product mixture was cooled over 10 min to 24° C. The cooled productmixture was transferred to a separatory funnel that had been chargedwith distilled water (300 mL) and 50% ethyl acetate-hexanes (v/v, 500mL). The layers that formed were separated. The organic layer was washedsequentially with water (5×300 mL) and saturated aqueous sodium chloridesolution (2×300 mL). The washed organic layer was dried over sodiumsulfate. The dried solution was filtered and the filtrate wasconcentrated to afford the unpurified alcohol 11 as a pale-yellow solid(3.35 g). ¹H NMR analysis (400 MHz, CDCl₃) indicated >95% conversion tothe alcohol 11. The product so obtained was used directly in thefollowing step.

An analytically pure sample of the alcohol 11 was obtained byflash-column chromatography (eluting with 50% ethyl acetate-hexanes):

R_(f)=0.30 (50% ethyl acetate-hexanes, KMnO₄). ¹H NMR (500 MHz, CDCl₃,5:1 mixture of diastereomers): E-olefin (major diastereomer), δ 7.69 (d,1H, J=8.5 Hz, H₁), 6.64 (d, 1H, J=8.5 Hz, H₂), 6.12 (q, 1H, J=6.5 Hz,H₁₀), 3.89 (s, 3H, H₃), 3.54 (dd, 1H, J=6.0, 3.5 Hz, H₆), 3.29-3.27 (m,1H, H₅), 3.10 (dd, 1H, J=18.5, 6.5 Hz, H₄), 2.99 (d, 1H, J=17.5 Hz, H₄),2.59 (dd, 1H, J=13.5, 7.0 Hz, H₈), 1.79 (d, 3H, J=7.0 Hz, H₁₁),1.87-1.76 (m, 2H, H₇/H₈), 0.71 (d, 3H, J=7.5 Hz, H₉); Z-olefin (minordiastereomer), δ 7.78 (d, 1H, J=8.5 Hz, H₁), 6.67 (d, 1H, J=8.5 Hz, H₂),5.65 (q, 1H, J=7.5 Hz, H₁₀), 3.90 (s, 3H, H₃), 3.43 (dd, 1H, J=5.5, 3.5Hz, H₆), 3.17 (dd, 1H, J=18.0, 7.0 Hz, H₄), 2.94 (d, 1H, J=18.0 Hz, H₄),2.70 (dd, 1H, J=13.5, 7.5 Hz, H₈), 2.62-2.60 (m, 1H, H₅), 2.07 (d, 3H,J=7.0 Hz, H₁₁),1.87-1.76 (m, 2H, H₇/H₈), 0.68 (d, 3H, J=7.5 Hz, H₉). ¹³CNMR (125 MHz, CDCl₃, 5:1 mixture of diastereomers): E-olefin (majordiastereomer), δ 163.5 (C), 152.3 (C), 137.7 (CH), 131.5 (C), 126.4 (C),122.0 (C), 120.4 (CH), 109.7 (CH), 78.4 (CH), 53.8 (CH₃), 44.7 (CH₂),44.5 (C), 39.1 (CH), 37.9 (CH₂), 34.2 (CH), 17.9 (CH₃), 12.8 (CH₃);Z-olefin (minor diastereomer), δ 163.5 (C),152.6 (C),137.5 (CH), 129.8(C), 126.0 (C), 122.8 (CH), 122.0 (C), 109.7 (CH), 77.9 (CH), 53.8(CH₃), 49.3 (CH), 45.5 (CH₂), 44.5 (C), 37.9 (CH₂), 34.2 (CH), 17.9(CH₃), 12.8 (CH₃). IR (ATR-FTIR), cm⁻¹: 3431 (br), 2925 (br), 1598 (m),1577 (w), 1476 (s), 1422 (m), 1323 (m), 1267 (m), 1033 (m), 828 (w), 658(w). HRMS-CI(m/z): [M+H]+ calcd for C₁₇H₂₁N₂O₂, 285.1598; found,285.1597.

Step 3b: Dehydration of the Tamao-Fleming Oxidation Product 11 (Alkene16)

A 100-mL round-bottomed flask fused to a Teflon-coated valve was chargedsequentially with the unpurified Tamao-Fleming oxidation product 11(11.8 mmol, 1.00 equiv, assuming quantitative yield in the preceedingstep) and methyl N-(triethylammoniumsulfonyl)carbamate 12 (3.09 g, 13.0mmol, 1.10 equiv). Benzene (10 mL) was added and the resulting solutionwas stirred for 15 min at 24° C. The solution was concentrated todryness and the residue obtained was redissolved in toluene (59 mL). Thereaction vessel was sealed and the sealed vessel was placed in an oilbath that had been preheated to 110° C. The reaction mixture was stirredand heated for 12 h at 110° C. The product mixture was cooled over 30min to 24° C. The cooled product mixture was diluted with ethyl acetate(200 mL) and the diluted solution was transferred to a separatory funnelthat had been charged with saturated aqueous sodium bicarbonate solution(200 mL). The layers that formed were separated. The aqueous layer wasextracted with ethyl acetate (200 mL). The organic layers were combinedand the combined organic layers were dried over sodium sulfate. Thedried solution was filtered and the filtrate was concentrated to affordthe alkene 16 as an off-white solid (3.19 g). ¹H NMR analysis (400 MHz,CDCl₃) indicated >95% conversion to the alkene 16. The product soobtained was used directly in the following step. An analytically puresample of the alkene 16 was obtained by flash-column chromatography(eluting with 10% ethyl acetate-hexanes):

R_(f)=0.32 (10% ethyl acetate-hexanes, KMnO₄). ¹H NMR (400 MHz, CDCl₃,5:1 mixture of diastereomers): E-olefin (major diastereomer), δ 7.70 (d,1H, J=8.8 Hz, H₁), 6.63 (d, 1H, J=8.8 Hz, H₂), 5.95 (q, 1H, J=6.8 Hz,H₉), 5.48 (m, 1H, H₆), 3.89 (s, 3H, H₃), 3.62 (m, 1H, H₅), 2.98 (dd, 1H,J=17.2, 5.2 Hz, H₄), 2.88-2.80 (m, 2H, H₄/H₇), 2.38 (d, 1H, J=16.8 Hz,H₇), 1.76 (d, 3H, J=6.8 Hz, H₁₀), 1.55 (s, 3H, H₈); Z-olefin (minordiastereomer), δ 7.78 (d, 1H, J=8.4 Hz, H₁), 6.66 (d, 1H, J=8.4 Hz, H₂),5.65 (q, 1H, J=7.2 Hz, H₉), 5.46 (d, 1H, J=4.8 Hz, H₆), 3.89 (s, 3H,H₃), 3.10-2.77 (m, 4H, 2×H₄/H₅/H₇), 2.38 (d, 1H, J=16.8 Hz, H₇), 2.06(d, 3H, J=7.6 Hz, H₁₀), 1.54 (s, 3H, H₈). ¹³C NMR (100 MHz, CDCl₃, 5:1mixture of diastereomer): E-olefin (major diastereomer), δ 163.5 (C),152.9 (C), 137.7 (CH), 132.3 (C), 130.7 (C), 125.2 (CH), 124.8 (C),121.7 (C), 116.7 (CH), 109.2 (CH), 53.7 (CH₃), 47.5 (CH₂), 44.6 (C),39.8 (CH₂), 31.6 (CH), 22.6 (CH₃), 12.7 (CH₃); Z-olefin (minordiastereomer), δ 163.5 (C), 153.2 (C), 137.7 (CH), 130.9 (C), 130.2 (C),126.3 (CH), 124.6 (C), 121.7 (C), 119.0 (CH), 109.3 (CH), 53.7 (CH₃),48.3 (CH₂), 42.1 (CH), 40.7 (CH₂), 40.1 (C), 22.5 (CH₃), 12.3 (CH₃). IR(ATR-FTIR), cm⁻¹: 2934 (br), 1598 (m), 1576 (w), 1476 (s), 1421 (m),1323 (m), 1268 (m), 1028 (w), 826 (w). HRMS-CI(m/z): [M+H]⁺ calcd forC₁₇H₁₉N₂O, 267.1492; found, 267.1492.

Step 3c: Hydrolysis of the Nitrile 16 (Amide 14)

Hydrido(hydroxydimethylphosphino)[hydrogenbis(hydroxydimethylphosphino)]platinum(II) (13, 101 mg, 240 μmol, 0.02 equiv) was added to a solution of theunpurified nitrile 16 (11.8 mmol, 1.00 equiv, assuming quantitativeyield in the preceeding step) in ethanol (6.6 mL) and water (3.3 mL) at24° C. The resulting mixture was placed in an oil bath that had beenpreheated to 95° C. The reaction mixture was stirred and heated for 24 hat 95° C. The product mixture was cooled over 10 min to 24° C. Thecooled mixture was concentrated to dryness. The residue obtained wasdissolved in dichloromethane (15 mL) and chloroform (15 mL), and theresulting solution was filtered through a pad of sodium sulfate. Thefiltrate was concentrated to afford the amide 14 as an off-white solid(3.60 g). ¹H NMR analysis (400 MHz, CDCl₃) indicated >95% conversion tothe amide 14. The product so obtained was used directly in the followingstep. An analytically pure sample of the amide 14 was obtained byflash-column chromatography (eluting with 50% ethyl acetate-hexanes):

R_(f)=0.20 (50% ethyl acetate-hexanes, KMnO₄). ¹H NMR (500 MHz, CDCl₃,5:1 mixture of diastereomers): E-olefin (major diastereomer), δ 7.33 (d,1H, J=8.5 Hz, H₁), 6.57 (d, 1H, J=8.5 Hz, H₂), 5.62 (br s, 1H, H₁₁),5.40 (q, 1H, J=7.0 Hz, H₉), 5.38-5.35 (m, 1H, H₆), 5.17 (br s, 1H, H₁₁),3.90 (s, 3H, H₃), 3.60 (m, 1H, H₅), 3.09-3.01 (m, 2H, H₄/H₇), 2.88 (d,1H, J=16.5 Hz, H₄), 2.11 (d, 1H, J=17.5 Hz, H₇), 1.70 (d, 3H, J=7.0 Hz,H₁₀), 1.53 (s, 3H, H₈); Z-olefin (minor diastereomer), δ 7.37 (d, 1H,J=8.4 Hz, H₁), 6.58 (d, 1H, J=8.4 Hz, H₂), 5.58 (br s, 1H, H₁₁), 5.54(q, 1H, J=16.5 Hz, H₉), 5.38-5.35 (m, 1H, H₆), 5.30 (br s, 1H, H₁₁),3.90 (s, 3H, H₃), 3.15-3.01 (m, 3H, H₄/H₅/H₇), 2.83 (d, 1H, J=16.5 Hz,H₄), 2.18 (d, 1H, J=17.0 Hz, H₇), 1.73 (d, 3H, J=7.5 Hz, H₁₀₀), 1.53 (s,3H, H₈); ¹³C NMR (125 MHz, CDCl₃, 5:1 mixture of diastereomer): E-olefin(major diastereomer), δ 176.9 (C), 162.9 (C), 153.8 (C), 138.9 (CH),138.1 (C), 133.7 (C), 128.5 (C), 124.1 (CH), 115.3 (CH), 108.9 (CH),54.4 (C), 53.7 (CH₃), 45.3 (CH₂), 39.8 (CH₂), 33.0 (CH), 23.0 (CH₃),13.0 (CH₃); Z-olefin (minor diastereomer), δ 178.4 (C), 162.9 (C), 153.1(C), 138.5 (CH), 137.1 (C), 133.6 (C), 128.3 (C), 125.9 (CH), 117.5(CH), 109.2 (CH), 53.7 (CH₃), 51.2 (C), 45.1 (CH₂), 44.2 (CH), 39.7(CH₂), 23.0 (CH₃), 13.0 (CH₃). IR (ATR-FTIR), cm⁻¹: HRMS-CI(m/z): 3346(br), 2926 (br), 1710 (w), 1664 (s), 1597 (m), 1576 (w), 1475 (s), 1422(m), 1322 (m), 1267 (w), 1028 (m), 824 (w). [M+H]⁺ calcd for C₁₇H₂₁N₂O₂,285.1598; found, 285.1601.

Step 3d: Conversation of the Amide 14 to (−)-Huperzine A (1)

[Bis(trifluoroacetoxy)iodo]benzene (5.58 g, 13.0 mmol, 1.10 equiv) wasadded to a stirred solution of the unpurified amide 14 (11.8 mmol, 1.00equiv, assuming quantitative yield in the preceeding step) in methanol(240 mL). The resulting mixture was heated to reflux (bathtemperature=65° C.). The reaction mixture was stirred and heated for 2 hat 65° C. The product mixture was cooled over 30 min to 24° C. Thecooled mixture was concentrated to dryness. The residue obtained wasdissolved in chloroform (120 mL). Iodotrimethylsilane (8.40 mL, 59.0mmol, 5.00 equiv) was added, and the reaction mixture was heated toreflux (bath temperature=61° C.). The reaction mixture was stirred andheated for 3 h at 61° C. The mixture was then cooled over 30 min to 24°C. Methanol (120 mL) was added and the resulting mixture was heated toreflux (bath temperature=65° C.). The reaction mixture was stirred andheated for 12 h at 65° C. The product mixture was then cooled over 30min to 24° C. The cooled product mixture was concentrated to dryness.The residue obtained was dissolved in 50% dichloromethane-chloroform(v/v, 200 mL). The resulting solution was transferred to a separatoryfunnel that had been charged with 1.0 N aqueous sulfuric acid solution(200 mL). The layers that formed were separated. The aqueous layer wasthen extracted with 50% dichloromethane-chloroform (v/v, 2×200 mL). Theorganic layers were combined and discarded. The aqueous layer wasbasified with saturated aqueous ammonium hydroxide solution (100 mL,final pH=12-13). The basified aqueous layer was extracted with 50%dichloromethane-chloroform (v/v, 4×200 mL). The organic layers werecombined and the combined organic layers were dried over sodium sulfate.The dried solution was filtered and the filtrate was concentrated. Theresidue obtained was purified by flash-column chromatography (elutingwith 10% methanol-ethyl acetate) to yield (−)-huperzine A (1, 1.61 g,56%, off-white solid) and the olefin isomer (iso-huperzine A, 17, 310mg, 11%, off-white solid).

Synthetic (−)-huperzine A (1) was identical in all respects [¹H NMR, ¹³CNMR, LC/MS retention time, IR, TLC solvent systems (10% methanol-ethylacetate, 5% methanol-dichloromethane, 5% methanol-dichloromethane+1%ammonium hydroxide) and optical rotation] to an authentic sample.

(−)-huperzine A (1): R_(f)=0.15 (10% methanol-ethyl acetate, KMnO₄).t_(R)=0.91. [α]²⁰ _(n)−144 (c 0.23, CHCl₃), lit. [α]²⁰ _(n)=−150 (c0.12, CHCl₃).¹⁰ ¹H NMR (500 MHz, CDCl₃), δ 13.25 (br s, 1H, H₃), 7.88(d, 1H, J=9.5 Hz, H₁), 6.37 (d, 1H, J=9.0 Hz, H₂), 5.46 (q, 1H, J=6.5Hz, H₉), 5.38 (d, 1H, J=4.5 Hz, H₆), 3.59-3.55 (m, 1H, H₅), 2.86 (dd,1H, J=17.0, 5.0, H₄), 2.73 (dd, 1H, J=16.5, 1.0 Hz, H₄), 2.12 (app s,2H, H₇), 1.88 (br s, 2H, H₁₁), 1.64 (d, 3H, J=6.5 Hz, H₁₀), 1.51 (s, 3H,H₈).¹³C NMR (125 MHz, CDCl₃), δ 165.5 (C), 143.3 (C), 142.4 (C), 140.3(CH), 134.1 (C), 124.4 (CH), 122.8 (C), 117.1 (CH), 111.4 (CH), 54.5(C), 49.2 (CH₂), 35.4 (CH₂), 33.0 (CH), 22.7 (CH₃), 12.5 (CH₃). IR(ATR-FTIR), cm⁻¹: 3355 (br), 1644 (s), 1608 (s), 1552 (m), 1452 (m),1121 (m), 837 (m). HRMS-CI(m/z): [M+H]⁺ calcd for C₁₅H₁₉N₂O, 243.1492;found, 243.1493.

iso-huperzine A (17): R_(f) ⁼0.15 (5% methanol-dichloromethane+1%ammonium hydroxide, KMnO₄). [α]²⁰ _(n)=−121 (c 0.01, CHCl₃). ¹H NMR (400MHz, CDCl₃), δ 13.10 (br s, 1H, H₃), 7.86 (d, 1H, J=9.6 Hz, H₁), 6.42(d, 1H, J=9.6 Hz, H₂), 5.41 (q, 1H, J=7.2 Hz, H₉), 5.37 (br s, 1H, H₆),3.00-2.88 (m, 2H, H₄/H₅), 2.70 (d, 1H, J=16.0 Hz, H₄), 2.40 (d, 1H,J=16.8, H₇), 2.05 (d, 1H, H₇), 1.93 (d, 3H, J=7.2 Hz, H₁₀), 1.90 (br s,2H, H₁₁), 1.53 (s, 3H, H₈). ¹³C NMR (100 MHz, CDCl₃), δ 165.5 (C), 143.4(C), 140.2 (C), 140.0 (CH), 133.7 (C), 125.4 (CH), 123.0 (C), 117.3(CH), 115.7 (CH), 56.6 (C), 49.8 (CH₂), 44.0 (CH), 36.4 (CH₂), 22.6(CH₃), 14.0 (CH₃). IR (ATR-FTIR), cm¹: 3380 (br), 2909 (br), 1653 (s),1611 (m), 1551 (m), 1459 (m), 833 (m), 755 (m), 651 (m). HRMS-CI(m/z):[M+H]⁺ calcd for C₁₅H₁₉N₂O, 243.1492; found, 243.1494.

EXPERIMENTAL SECTION REFERENCES

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BACKGROUND AND DETAILED DESCRIPTION OF THE INVENTION REFERENCES

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1. (canceled)
 2. (canceled)
 3. (canceled)
 4. (canceled)
 5. (canceled) 6.(canceled)
 7. (canceled)
 8. (canceled)
 9. (canceled)
 10. (canceled) 11.(canceled)
 12. (canceled)
 13. A compound of the formula (I):

wherein: R₁ is selected from the group consisting of substituted orunsubstituted C₁-C₆ alkyl and substituted or unsubstituted ether; R₂ andR₅ are independently selected from the group consisting of H,substituted or unsubstituted C₁-C₆ alkyl, and CN, provided that when oneof R₂ or R₅ is CN, the other must be H; X is halogen; R₃ at eachoccurrence is independently selected from the group consisting of H,substituted or unsubstituted C₁-C₆ alkyl, ether, amino, and alkoxy; R₄is selected from the group consisting of Si(CH₃)₂Ph, substituted orunsubstituted C₁-C₆ alkyl, substituted or unsubstituted C₁-C₆ alkenyl,substituted or unsubstituted aryl, and substituted or unsubstitutedheteroaryl; A is C, N, or S; m is 0, 1, or 2; n is 0 or 1; or apharmaceutically acceptable salt, enantiomer, diasteromer, solvate orpolymorph thereof.
 14. The compound of claim 13, or a pharmaceuticallyacceptable salt, enantiomer, diastereomer, solvate or polymorph thereof,wherein the compound is:


15. A compound of the formula (II):

wherein: R₁ is selected from the group consisting of substituted orunsubstituted C₁-C₆ alkyl and substituted or unsubstituted ether; R₂ andR₅ are independently selected from the group consisting of H andsubstituted or unsubstituted C₁-C₆ alkyl; R₃ at each occurrence isindependently selected from the group consisting of H, substituted orunsubstituted C₁-C₆ alkyl, ether, amino, and alkoxy; R₄ is selected fromthe group consisting of H, OH, and Si(CH₃)₂Ph; R₆ is selected from thegroup consisting of NH₂, amide, CN, a carboxylic acid derivative, analcohol, or an aldehyde; R₇ is substituted or unsubstituted C₁-C₆ alkyl,ester, or substituted or unsubstituted aryl; A is C, N, or S; and n is 0or 1; or a pharmaceutically acceptable salt, enantiomer, diastereomer,solvate or polymorph thereof.
 16. The compound of claim 15, or apharmaceutically acceptable salt, enantiomer, diastereomer, solvate orpolymorph thereof, wherein the compound is selected from the groupconsisting of:

Where R¹ and R² are each independently H or a C₁-C₆ alkyl group;

and its primary amine derivatives wherein CN is converted to a CH₂NR¹R²group where R¹ and R² are each independently H or a C₁-C₆ alkyl group;and

and its primary amine derivatives wherein CN is converted to a CH₂NR¹R²group where R¹ and R² are each independently H or a C₁-C₆ alkyl group;17. (canceled)
 18. (canceled)
 19. (canceled)
 20. (canceled) 21.(canceled)
 22. (canceled)
 23. (canceled)
 24. (canceled)
 25. (canceled)26. (canceled)
 27. (canceled)
 28. (canceled)
 29. (canceled) 30.(canceled)
 31. (canceled)
 32. (canceled)
 33. (canceled)
 34. (canceled)35. (canceled)
 36. A compound of the formula (VIII):

wherein: R₁ is selected from the group consisting of substituted orunsubstituted C₁-C₆ alkyl and substituted or unsubstituted ether; R₂ andR₅ are independently selected from the group consisting of H andsubstituted or unsubstituted C₁-C₆ alkyl; R₃ at each occurrence isindependently selected from the group consisting of H, substituted orunsubstituted C₁-C₆ alkyl, ether, amino, and alkoxy; A is C, N, or S;and n is 0 or 1; or a pharmaceutically acceptable salt, enantiomer,diastereomer solvate or polymorph thereof.
 37. A compound of claim 36,or a pharmaceutically acceptable salt, enantiomer, diastereomer solvateor polymorph thereof, wherein the compound is:


38. (canceled)
 39. (canceled)
 40. (canceled)
 41. (canceled) 42.(canceled)
 43. (canceled)
 44. (canceled)